A U.S. Marine helicopter's "hard landing" near the North Korean border left 21 service members injured early Tuesday, officials said.

The CH-53E Super Stallion chopper was "conducting routine flight operations" during an exercise near South Korea's Jipo-ri Range at the time of the incident, according to a military statement.

All 21 personnel aboard were hospitalized but 15 were treated and released. Six remained in stable condition.

Its crew was from the 31st Marine Expeditionary Unit and is stationed in Okinawa, Japan.

South Korea's Yonhap News Agency reported that the aircraft caught fire following the incident, which it said occurred about 55 miles north of Seoul. NBC News could not immediately independently verify those details.

The military statement added: "Safety is a priority for all aircraft operations. The CH-53E has an excellent operational safety record. A comprehensive investigation will take place to determine the facts and circumstances surrounding this incident."

Neighboring North Korea has threatened nuclear attacks on the United States, South Korea and Japan after new U.N. sanctions were imposed in response to its latest nuclear arms test in February.

The North has also been angry about annual military exercises between U.S. and South Korean forces, describing them as a "hostile" act. The United States dispatched stealth bombers from their bases to take part. 

Reuters contributed to this report.

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Full North Korea coverage from NBC News

This story was originally published on Tue Apr 16, 2013 4:02 AM EDT

TOKYO -- Secretary of State John Kerry has called on China to do more to help resolve the North Korean missile crisis, saying the country provided the Pyongyang regime with a “lifeline.”

In an interview with NBC's TODAY that aired on Monday, Kerry also said any deal with the rogue state would need to be structured so that Pyongyang could not later renege on its terms.

The crisis developed after North Korea threatened to carry out a pre-emptive nuclear strike against its enemies in response to United Nations sanctions imposed because of an underground nuclear test in February and a rocket test in December.

In recent days the North Koreans have readied missiles for launch and some speculated this would happen on Monday, when the nation celebrates the birth of founder Kim Il Sung, current leader Kim Jong Un’s grandfather.

In an interview in Tokyo before flying back to the U.S. on Monday, Kerry said that if the missiles were not fired “that would mean perhaps we're turning a corner and there's a possibility of moving in a better direction.”

“Everybody understands the negative side of what happens if there is a shoot.  And my hope is that we can move in a different direction here. China, I think, is serious about this,” he said. “They understand the instability this is creating.”

Kerry said it was “very important” for the United States to make clear to North Korea that there would be “consequences for their action” and to reaffirm its security agreements with its allies in the region.

“That done, I think it is very important to the Chinese to focus on the fact that ... if they're not prepared to put the pressure on the North -- and they have the greatest ability to have an impact on the North -- then this can become more destabilizing,” he said. “And that instability is not in China's interest, certainly. It's not in anybody's interest in the region.”

“So if we're going to operate according to what's in people's interest, China's and everybody else's, I believe China needs to become more engaged in this effort,” he said.

“It is obvious that China is the lifeline to North Korea. Everybody knows that China provides the vast majority of the fuel to North Korea.  China is their biggest trading party, their biggest food donor and so forth,” he added.

When asked about a comment by Sen. John McCain, R-Ariz., that North Korea had a history of breaking diplomatic deals, Kerry replied: "John is absolutely correct, that has been the pattern. And I have raised that issue with the Chinese … There has been a history of ... just playing this game and then ultimately there's cheating or a complete reneging. We are determined, I am determined to try to find if there is a different formula.  And that is a … conversation that I specifically had with the Chinese.”

On Sunday, Kerry said the United States was prepared to “reach out” to North Korea’s leadership.

The United States has offered talks, but on the precondition that North Korea abandon its nuclear weapons ambitions. North Korea deems its nuclear arms a "treasured sword" and has vowed never to give them up.

On Monday, North Korean state media made hardly a mention of conflict in contrast to weeks of tirades against its enemies in what some saw as good sign.

"South Korea and the United States have sent a message for dialogue, so for now the North is switching to that mode," Yang Moo-jin, of the University of North Korean Studies in Seoul, told Reuters. "The North's strategic intention has been to try to get some kind of response from the United States and South Korea and now they have that. They won't be brushing away the suggestions to enter dialogue lightly." 

'Bright faces'
In Pyongyang on Monday, residents spilled into the streets in apparent celebration, The Associated Press reported. Girls in red and pink jackets skipped along streets festooned with celebratory banners and flags and parents pushed strollers with babies bundled up against the chill.

"Although the situation is tense, people have got bright faces and are very happy," Han Kyong Sim, a drink stand worker, told the AP. 

Slideshow: North Korea's young leader, Kim Jong Un

The youngest son of Kim Jong Il succeeded his late father in 2011, becoming the third member of his family to rule the unpredictable and reclusive communist state.

Launch slideshow

North Korea's state-controlled KCNA news agency reported that Kim Jong Un had received a letter from the Central Committee of the Anti-Imperialist National Democratic Front that praised his grandfather.

“The life of Kim Il Sung was an epic-like one of an invincible hero who clarified the truth that arms are a lifeline of the nation and guarantees the victory of revolution, restored the country by leading to victory the hard-fought battles against the Japanese and the U.S. imperialists,” the letter said.

The letter “pledged to join the all-people resistance to frustrate the frantic moves of the hostile forces for a nuclear war and make positive contribution to bringing about a fresh turn in the efforts for national reunification,” KCNA said.

South Korea's Defense Ministry said it remained on guard against any missile launch to coincide with Kim Il Sung’s birth, Reuters reported.

"The military is not easing up on its vigilance on the activities of the North's military with the view that they can conduct a provocation at any time," a ministry spokesman said. 

Reuters and The Associated Press contributed to this report.

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Full North Korea coverage from NBC News

This story was originally published on Mon Apr 15, 2013 7:01 AM EDT

As North Korea continues its bellicose rhetoric, the U.S., as well as China and the rest of Asia are on high alert.

A team of NBC News correspondents have been deployed to cover the potential impact of a missile launch: Richard Engel is in Seoul, South Korea;  Ian Williams is in Beijing, China; and Ayman Mohyeldin is in Tokyo, Japan.

On Friday, they all participated in a Google+ Hangout and discussed the attitudes in their respective countries towards North Korea's rhetoric, the real potential of a missile launch and much more.

Ian Williams weighed in from Beijing saying that the North Korea story has recently generated an “explosion of interest” in the official Chinese state media over the last few days. But what he finds even more significant is the attention the story is getting on social media in China.

Left to right: Ayman Mohyeldin, Richard Engel, Ian Williams.

“Social media, the Internet, is the closest barometer we have got of public opinion here in China. And they are absolutely laying into North Korea. The criticism is  – not of the U.S. – but of North Korea. There are caricatures, there are cartoons, they’ve dubbed the leader Kim Jong Un as ‘Fatty the Third’ or ‘Little Fatty,” Williams reported. Adding “It’s serious – they are questioning precisely what he’s going to stick on top of one of his missiles, questioning the military capability. But also criticizing their own leadership for their association with what they see as a Neanderthal regime whose methods are very chilling.”

Click on the link above to replay the informative chat from three of NBC’s most experienced foreign correspondents.

This story was originally published on Thu Apr 11, 2013 7:10 PM EDT

SEOUL -- The United States and South Korea were on high alert for a North Korean missile launch on Thursday as the hermit kingdom turned its attention to celebrating its ruling Kim dynasty and appeared to tone down rhetoric of impending war.

Despite threats it will attack U.S. bases and the South in response to any hostile acts, North Korea started to welcome a stream of visitors for Monday's birthday celebrations of its founding father, Kim Il Sung.

North Korea has stationed as many as five medium-range missiles on its east coast, according to defense assessments made by Washington and Seoul, possibly in readiness for a test launch that would demonstrate its ability to hit U.S. bases on Guam.

Most observers say Pyongyang has no intention of igniting a conflict that could bring its own destruction but warn of the risks of miscalculation on the highly militarized Korean peninsula.

In London, G8 foreign ministers condemned North Korea's development of nuclear weapons and ballistic missile technology "in the strongest possible terms" in an agreed statement.

There did not appear to be any signs of panic in Seoul, the South Korean capital, and financial markets appeared to shrug off the risk of conflict with stocks posting a third day of gains.

Taiwan appeared to become the first country to warn its citizens against travelling to South Korea after a warning from Pyongyang that foreigners should leave, but hotels were reporting brisk business.

Pyongyang issued a statement that appeared to be tinged with regret over the closure of the joint Kaesong industrial zone that was shuttered when it ordered its workers out this week, terming the North-South Korean venture "the pinnacle of General Kim Jong Il's limitless love for his people and brothers".

The statement on the country's KCNA news agency blamed South Korean President Park Geun-hye for bringing the money-spinning venture to "the brink of shutting down."

Kim Jong Il, Kim Il Sung's son, ruled North Korea until his death in December 2011. He was succeeded by Kim Jong Un, the third of his line to preside over one of the world's poorest and most heavily militarized countries.

Since taking office, the 30-year-old has staged two long-range rocket launches and a nuclear weapons test. The nuclear test in February triggered U.N. sanctions that Pyongyang has termed a hostile act and a precursor to invasion.

For over a month, Pyongyang has issued an almost daily series of threats to the United States and South Korea, most recently warning foreigners to leave the South due to an impending "thermonuclear" war.

Slideshow: North Korea's young leader, Kim Jong Un

The youngest son of Kim Jong Il succeeded his late father in 2011, becoming the third member of his family to rule the unpredictable and reclusive communist state.

Launch slideshow

Apart from the swipe at South Korea's new president, verbal threats appeared to fall off as KCNA listed arrivals for the upcoming birthday celebrations, naming an eclectic mix ranging from Chinese businessmen to Cold War-era enthusiasts of its socialist monarchy and official ideology of "Juche," or self-reliance.

Reinforcing the rule of the Kim dynasty and the legitimacy of the latest Kim to hold power in Pyongyang is a key tenet of North Korea's ideology.

It was the first anniversary on Thursday of Kim's official ascent to power, although he became de-facto leader immediately after his father's death.

The North's rhetoric has pushed the United States, the guarantor of South Korea's security, to move more military assets into the region in response to the rising threat levels.

In Washington, Defense Secretary Chuck Hagel warned on Wednesday that the North was "skating very close to a dangerous line" with its threats and provocations, and said the United States, currently involved in military exercises with South Korea, was prepared to respond to any moves by Pyongyang.

"We have every capacity to deal with any action that North Korea would take, to protect this country and the interests of this country and our allies," Hagel told reporters at the Pentagon.

China, the North's only major diplomatic ally, has watched the situation evolving on its doorstep with concern.

"China respects North Korea, but it also holds the responsibility of preserving peace in Northeast Asia," the Global Times, a tabloid published by the ruling Communist Party's People's Daily, said in an editorial.

"Pyongyang should drop its illusions that it can make the world stay silent over its desire for nuclear arms through its hard-line stance and deceptions. We believe the North still has a chance and we regret that it has become mired in this crisis. We hope the crisis is only temporary."

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Full North Korea coverage from NBC News

This story was originally published on Thu Apr 11, 2013 3:45 AM EDT

U.S. defense officials are "highly confident" that North Korea is planning the imminent launch of a medium-range missile, echoing warnings from South Korea that the probability of Pyongyang carrying out its threat is "very high."

Pentagon officials say they believe the rogue communist state is preparing to fire one or more Musadan missiles from its east coast.

The North has been threatening the United States and its "puppet" South Korea almost daily in recent weeks, and the Commander of U.S. Pacific Command told Congress on Tuesday that he could not recollect a more tense time in the region since the end of the Korean War.

Slideshow: North Korea's young leader, Kim Jong Un

The youngest son of Kim Jong Il succeeded his late father in 2011, becoming the third member of his family to rule the unpredictable and reclusive communist state.

Launch slideshow

World leaders have shown alarm at the prospects of a conflict.

"According to intelligence obtained by our side and the U.S., the possibility of a missile launch by North Korea is very high,” South Korea’s Foreign Minister Yun Byung-se told a parliamentary hearing in Seoul, according to Reuters.

Musudan missiles could be launched "at any time from now,” he said.

U.S. defense chiefs have echoed that belief, acknowledging that North Korea has placed a Musadan missile -- which has a range of roughly 1,800 to 2,100 miles, with a minimum range of about 400 miles -- on its east coast.

On Wednesday Secretary of Defense Chuck Hagel said that the U.S. is "fully prepared to deal with any contingency" or provocation that North Korea may take, but added that the U.S. hopes the rhetoric will be "ratcheted down."

Speaking at the Pentagon budget rollout briefing, Hagel said that the U.S., the UN, and U.S. allies have made clear to North Korea that Kim Jung Un is "skating very close to a dangerous line," and that his actions and words are not helping to "diffuse the combustible situation."

Navy Adm. Sam Locklear told members of the Senate Armed Services Committee on Tuesday that the U.S. is ready to respond to a North Korean missile launch or other threat.

"I am satisfied that we are ready today, yes," Locklear said.

Asked specifically whether U.S. forces can intercept a missile from North Korea, Locklear said: "I believe we have a credible ability to defend the homeland, to defend Hawaii, defend Guam, to defend our forward-deployed forces and defend our allies."

He went on to say that the U.S. was in a position to intercept a missile even if one were launched imminently.

Meanwhile, Chinese authorities in the northeastern city of Dandong told tour agencies to halt overland tourism into North Korea, local travel agents said Wednesday.

"All (tourist) travel to North Korea has been stopped from today, and I've no idea when it will restart," a travel agent in Dandong told Reuters.

And despite the taunts from North Korea, which include a warning for foreigners to leave the South, State Department spokesman Patrick Ventrell said no new security warnings were being issued to Americans in South Korea or those planning to travel there.

"There's no specific information to suggest imminent threat to U.S. citizens or facilities in the Republic of Korea,” he added. “So the U.S. Embassy has not changed its security posture. We have not recommended that U.S. citizens who reside in or plan to visit the Republic of Korea take special security precautions at this time."

Amid the regional tension, South Korea blamed Pyongyang for a cyberattack that shut down tens of thousands of computers and servers at banks last month.

Investigators detected similarities between the March cyberattack and past hacking attributed to the North Korean spy agency, including the recycling of 30 previously used malware programs — out of a total of 76 used in the attack, said Chun Kil-soo, an official at South Korea's Internet security agency.

NBC News' Jim Maceda and Jeff Black contributed to this report.

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This story was originally published on Wed Apr 10, 2013 7:08 PM EDT

SEOUL - North Korea warned foreigners in South Korea on Tuesday to leave the country because they were at risk in the event of conflict, the latest threat of war from Pyongyang.

Soaring tensions on the peninsula have been fuelled by North Korean anger over the imposition of U.N. sanctions after its last nuclear arms test in February, creating one of the worst crises since the end of the Korean War in 1953.

"We do not wish harm on foreigners in South Korea should there be a war," said the KCNA news agency, citing its Korea Asia-Pacific Peace Committee.

KCNA said once war broke out "it will be an all-out war, a merciless, sacred, retaliatory war to be waged by (North Korea)."

They added, "the committee informs all foreign institutions and enterprises and foreigners, including tourists...that they are requested to take measures for shelter and evacuation in advance for their safety."

Pyongyang last week advised embassies there to consider pulling out in case of war. Earlier on Tuesday, North Korean workers failed to turn up at a factory complex operated with South Korea, effectively shutting down the last major symbol of cooperation between the hostile neighbors.

Few embassies in Seoul have advised their citizens to quit. The United States, which has also been threatened by Pyongyang, has said there were no imminent signs of threats to American citizens.

Pyongyang has shown no sign of preparing its 1.2 million-strong army for war, indicating the threats could be partly intended for domestic purposes to bolster Kim Jong Un, 30, the third in his family to lead the reclusive country.

South Korea's president said she was disappointed at North Korea's decision to halt operations at the Kaesong industrial park, which generates $2 billion in trade for the impoverished state.

News of the Kaesong closure diverted attention from speculation that the North was about to launch some sort of provocative act this week -- perhaps a missile launch or new nuclear test. However, residents of Seoul carried on with daily activities with no trace of anxiety.

Few experts had expected Pyongyang to jeopardize Kaesong, which employs more than 50,000 North Koreans making household goods for 123 South Korean firms.

World leaders have expressed alarm at the crisis and the prospect of a conflict involving a country claiming to be developing nuclear weapons.

China, the North's sole diplomatic and financial ally, has shown increasing impatience with Pyongyang. Russian President Vladimir Putin said hostilities could create a cataclysm worse than the 1986 Chernobyl nuclear disaster.

The North is also angry at weeks of joint U.S.-South Korean military exercises off the coast of the peninsula, with B-2 stealth bombers dispatched from their U.S. bases.

But the United States announced the postponement last weekend of a long-planned missile launch, a move officials said was aimed at easing tensions on the peninsula.

North Korean authorities told embassies in Pyongyang they could not guarantee their safety from Wednesday, after saying conflict was inevitable amid the joint U.S.-South Korean military exercises due to last until the end of the month. No diplomats appear to have left the North Korean capital.

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Full North Korea coverage from NBC News

Who is North Korea's secretive leader? Here is what we know

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The latest threat of war from North Korea came Tuesday as Pyongyang warned foreigners in South Korea to leave the country because they were at risk in the event of conflict. Soaring tensions in the region have been fueled by North Korean anger over the imposition of U.N. sanctions after its last nuclear arms test in February.

NBC News chief foreign correspondent Richard Engel participated in a Google+ Hangout on Tuesday from Seoul. He answered questions on the deteriorating situation in the region, the North’s nuclear test plans and more.   

Click on the video above to replay the informative chat.

See more of Richard's reporting on NBC's Nightly News with Brian Williams tonight, the Today Show, MSNBC cable and here on NBCNews.com.

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Ahn Young-Joon / AP

Crowds of people shop at Myeongdong, a main shopping street in Seoul, amid a tense situation over North Korea's threat of war, on Sunday.

SEOUL, South Korea – As the war drums keep beating on the Korean Peninsula, one would expect to see anxiety on the streets of Seoul, where 10 million people live just 30 miles from 700,000 North Korean soldiers and well within range of thousands of heavily dug-in artillery pieces. 

Instead, people in South Korea's capital have been calmly going about their business. No boarding up of homes or work places. No distribution of emergency drugs or gas masks. Restaurants and hotels are full. The city is bustling.

Don’t these people know that hundreds – or even thousands – could die if the North launches a full-scale attack, as it has threatened to do?

“It’s postive thinking,” explained Kwak Keumjoo, a professor of psychology at the Seoul National University. “If you keep thinking about fear and threats, life wouldn’t be worth it. So people here have a defense mechanism. They tell themselves, ‘OK, it will be all right’, or ‘Somebody will help us,’ or ‘I don’t believe it’s really going to happen.’”

Keumjoo said it’s not as much a state of denial as a numbness, brought about by living under a constant threat, 60 years after the bloody Korean War ended, not with a peace treaty, but with an open-ended cease-fire.

To survive, Seoulites rarely talk about the North. They bury their worry in the deep recesses of their minds and put their faith in their own system.

“South Koreans have the view that justice and democracy will always win out,” said Keumjoo.

‘We’re not worried about the war’
Yoo-Lim, In-Young and Na-Young are all sophomores at Seoul’s Ewha University. During a recent lunch break, none of them was gazing at the horizon, looking for a mushroom cloud.

“We read the papers, listen to the radio, go online,” said Yoo-lim. “And we’re not worried about the war.”

Why is she so calm when the media has reached a fever pitch? “Repetitive learning,” she replied. “The north has done this over and over.”

But what about fire drills? Getting under desks? Bracing under bunkers?

“No, there’s nothing like that,” said Na-Young in between giggles. “We’re just used to North Korean threats from time to time.”

That’s not to say Seoul lives in a fantasy world.

Jim Maceda / NBC News

An entrance to one of Seoul's many underground malls that also functions as a temporary shelter.

Shopping mall bunkers
Beneath its downtown streets, a maze of malls and passageways interconnect into one of the world’s largest underground shelters, big enough, officials say, to protect 2 million citizens from any potentially withering pounding by North Korea’s heavy conventional weapons – but not a nuclear attack.

Ironically, the malls are converted underground bunkers left derelict after the Korean War. Today, many buildings here have basement parking lots that descend six or seven levels, and serve as temporary shelters as well.

On the 15^th of most months, sirens announce the beginning of a 15-minute civil drill, where drivers are supposed to pull their vehicles over to the curb and head for the closest shelter, clearing the streets.

But, with no real alert taking place now for some 60 years, Seoulites have understandably become complacent. Drivers stay in their vehicles; pedestrians stop and keep chatting.

“If there was an attack I wouldn’t know where to go,” Julie Yoo, a freelance journalist, admitted.  

“The Korean men call their reserve units, government officials and bureaucrats have their specially designated shelters, but Korean women, like myself, have no option but to stay at home and watch TV for guidance.”

In fact, if there ever was a nuclear attack here, Seoul has only one bunker where you might survive that kind of attack – under the Presidential Palace.

Jim Maceda / NBC News

One of Seoul's many underground malls which also functions as a temporary shelter.

“But I’m not worried,” said Yoo. “It’ll never happen!”

‘We have to study!’
In towns along the border, news reports speak of some preparations, like pamphlets distributed to locals, advising them of what signs to look for – sudden thick clouds or large numbers of birds or fish mysteriously dying.

But only 30 miles away, In-Young has anything but war signals on her mind.

“No one is saying ‘Oh there’s gonna be a war, we’re all gonna die!,’” she blurted out. “No, all our friends care about are exams coming up in two weeks – we have to study!”

Jim Maceda is an NBC News foreign correspondent based in London, currently on assignment in Seoul, South Korea.

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North Korea warns foreigners to leave South

Full North Korea coverage from NBC News

Who is North Korea's secretive leader? Here is what we know

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