KCNA via Reuters

North Korean soldiers attend military drills that the country's state-controlled KCNA news agency said took place on Wednesday. Kim Jong Un reportedly said that "when the drills turn into a battle, the enemies will be made to drink a bitter cup."

Kim Jong Un said on Wednesday that North Korea would attack U.S. military bases in the Pacific in addition to South Korea if its “enemies … make even the slightest movement,” according to the North’s official KCNA news agency.

The North also hit out over deployment of a U.S. B-52 bomber to South Korea, warning of “all-out action” - the latest of a series of threats issued by Pyongyang.

KCNA news agency said, in its usual flowery rhetoric, that the presence of the bomber showed the U.S. was preparing for "a pre-emptive nuclear strike," echoing its own earlier threat to do that.

Tensions have risen sharply on the Korean peninsula following a rocket test by the North in December and a nuclear bomb test in February.  In response, the U.N. Security Council unanimously agreed early this month to impose further sanctions.

The threat to attack American bases in the Pacific came in a KCNA article headlined “Kim Jong Un Guides Drone Attack, Self-Propelled Flak Rocket Drills,” which trumpeted the success of a drill that was said to have destroyed an “enemy” cruise missile.

“When the drills turn into a battle, the enemies will be made to drink a bitter cup, unable to raise their heads, in the face of retaliatory blows of the strong revolutionary Paektusan army, he [Kim] said,” KCNA reported.

“He [Kim] said that if the enemies, oblivious of the tremendous might of the KPA, make even the slightest movement, he will give an order to destroy not only the military installments and puppet reactionary ruling institutions in the operational theater in south Korea but the relevant facilities of countries following the U.S. war moves for invading the DPRK, and the military bases of the U.S. imperialist aggression forces in the operational theatre of the Pacific,” it said.

“He continued that time has gone when only words were made, stressing the need to destroy the enemies without mercy so that not a single man can survive to sign a document of surrender when a battle starts,” it added.

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

U.S. 'better stop acting rashly'
Another KCNA article said Wednesday that the U.S. had become “evermore undisguised in its moves to make a pre-emptive nuclear strike” on North Korea and that this “goes to clearly show who is the arch criminal threatening peace on this land.”

“The U.S. imperialists had better stop acting rashly, properly understanding the will of the army and people that have turned out as one in an all-out action for a final victory,” it said.

North Korea routinely issues threats that sound alarming, but expert commentators have said the recent rhetoric has been stronger than in the past. North Korea has even said it has scrapped the armistice that ended the 1950-53 Korean War.

Reuters summarized current thinking about the threat posed by the North:

North Korea's missiles have the capacity to hit bases in Japan and on the island of Guam.

Most military experts say that the North will likely not launch an all-out war against South Korea and its U.S. ally due to its outdated weaponry.

Pyongyang is viewed as more likely to stage an attack along a disputed sea border between the two countries as it did in 2010 when it shelled a South Korean island, killing four people.

Such a move would provide a major test for new South Korean President Park Geun-hye who took office pledging closer ties with the North if it abandoned its nuclear push.

Reuters contributed to this report.

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Eric Talmadge / AP

A brown tree snake is held by U.S. Department of Agriculture wildlife specialist Tony Salas outside his office on Andersen Air Force Base on Guam. There may be 2 million of the reptiles on the island.

ANDERSEN AIR FORCE BASE, Guam -- Dead mice laced with painkillers are about to rain down on Guam's jungle canopy. They are scientists' prescription for a headache that has caused the tiny U.S. territory misery for more than 60 years: the brown tree snake.

Most of Guam's native bird species are extinct because of the snake, which reached the island's thick jungles by hitching rides from the South Pacific on U.S. military ships shortly after World War II.

There may be 2 million of the reptiles on Guam now, decimating wildlife, biting residents and even knocking out electricity by slithering onto power lines.

More than 3,000 miles away, environmental officials in Hawaii have long feared a similar invasion — which in their case likely would be a "snakes on a plane" scenario.

That would cost the state many vulnerable species and billions of dollars, but the risk will fall if Guam's airdrop strategy succeeds.

"We are taking this to a new phase," said Daniel Vice, assistant state director of U.S. Department of Agriculture's Wildlife Services in Hawaii, Guam, and the Pacific Islands. "There really is no other place in the world with a snake problem like Guam."

Brown tree snakes are generally a few feet long but can grow to be more than 10 feet in length.

Defenseless birds
Most of Guam's native birds were defenseless against the nocturnal, tree-based predators, and within a few decades of the reptile's arrival, nearly all of them were wiped out.

The snakes can also climb power poles and wires, causing blackouts, or slither into homes and bite people, including babies.

They use venom on their prey, but it is not lethal to humans.

The infestation and the toll it has taken on native wildlife have tarnished Guam's image as a tourism haven, though the snakes are rarely seen outside their jungle habitat.

The solution to this headache, fittingly enough, is acetaminophen, the active ingredient in painkillers including Tylenol.

The strategy takes advantage of the snake's two big weaknesses. Unlike most snakes, brown tree snakes are happy to eat prey they didn't kill themselves, and they are highly vulnerable to acetaminophen, which is harmless to humans.

The upcoming mice drop is targeted to hit snakes near Guam's sprawling Andersen Air Force Base, which is surrounded by heavy foliage and if compromised would offer the snakes a potential ticket off the island. Using helicopters, the dead neonatal mice will be dropped by hand, one by one.

U.S. government scientists have been perfecting the mice-drop strategy for more than a decade with support from the Department of Defense and the Department of the Interior.

Streamers
To keep the mice bait from dropping all the way to the ground, where it could be eaten by other animals or attract insects as they rot, researchers have developed a device with streamers designed to catch in the branches of the forest foliage, where the snakes live and feed.

Experts say the impact on other species will be minimal, particularly since the snakes have themselves wiped out the birds that might have been most at risk.

"One concern was that crows may eat mice with the toxicant," said William Pitt, of the U.S. National Wildlife Research Center's Hawaii Field Station. "However, there are no longer wild crows on Guam."

The mouse drop is set to start in April or May.

A 2010 study conducted by the National Wildlife Research Center found brown tree snakes would cause between $593 million and $2.14 billion in economic damage each year if they became established in Hawaii like they are on Guam.

Power outages would cause the most damage, followed by a projected decline in tourism. The cost of treating snake bites would account for a small share.

Native Hawaiian birds "literally don't know what to do when they see a snake coming," said Christy Martin, a spokeswoman for the Coordinating Group on Alien Pest Species, a partnership of Hawaii government agencies and private organizations.

"Once we get snakes here, we're never going to be able to fix the situation," Martin said. 

Related:

Full environment coverage from NBC News 

Full technology and science coverage from NBC News

Two Russian bombers, capable of carrying nuclear cruise missiles, circled the U.S. island of Guam in the Western Pacific this week, U.S. military officials told NBC News. U.S. Air Force F-15 jets scrambled from Andersen Air Force Base on Guam to intercept the bombers.

According to one military official, the Russian Bear bombers remained in international airspace, the encounter between the U.S. and Russian aircraft “stayed professional” and there was no incident. The official said it’s impossible to determine whether the Russian bombers carried any nuclear weapons.

U.S. long-range radars and satellites tracked the two bombers as they took off from northeastern Russia and headed south on a long-range flight that required “multiple refueling.” Japan also scrambled fighter jets as the bombers passed near but did not enter Japanese airspace.

U.S. military officials say “it’s highly unusual but not unprecedented” that Russian bombers would fly training missions in the vicinity of Guam. According to one official, “It wasn’t provocative but it certainly got our attention.” U.S. long-range B-52 bombers, also capable of carrying nuclear weapons, are based at Guam.

Since Vladimir Putin reclaimed the Russian presidency, U.S. officials said the number of such flights in the vicinity of the Aleutian Islands and Alaska have increased, but encounters with U.S. aircraft have remained “generally very professional.”

The two Russian Bear bombers flew near Guam at about the same time President Barack Obama delivered his State of the Union message. Military officials refused to speculate about the timing.

The interception was first reported in the Washington Free Beacon.

A man accused of killing two Japanese visitors and injuring a dozen others after crashing his car and stabbing people in a major tourist district in Guam has been arrested and faces multiple charges, police said Wednesday.

Chad Ryan DeSoto, 21, of Tamuning is accused of driving a Toyota Yaris onto a sidewalk and striking seven tourists Tuesday night at an upscale shopping area fronting the Outrigger Guam Resort in Tumon Bay, Guam police spokesman A.J. Balajadia said. DeSoto continued driving on the sidewalk, crashing into the wall of a convenience store. He then left his car and started stabbing people, police said.

DeSoto is charged with two counts of murder, 13 counts of attempted murder and 13 counts of aggravated assault, Balajadia said. No motive or other details on the investigation were released.

DeSoto was scheduled due to appear before a magistrate judge at the Superior Court of Guam on Wednesday to be formally charged.

Japan Chief Cabinet Secretary Yoshihide Suga said 14 Japanese tourists were attacked, including two who died. Two of the injured have been released from the hospital after being treated, Suga said.

Japanese media reported the dead were two women aged 28 and 82 and the survivors included an 8-month-old baby.

An official with Japanese travel operator H.I.S. Co. said eight of its customers were injured in the attack -- including some with broken bones -- but none was killed.

The wreck and alleged knife attack among high-end boutiques and hotels in Tumon Bay's Pleasure Island district sent frightened hotel guests and others fleeing for safety.

A woman at a nearby café with friends told the Pacific Daily News she saw the car plow through the driveway and into a convenience store at the resort. Ashley Quichocho, 18, of Dededo said the driver got out, ran up to bystanders and began stabbing them.

"He started stabbing someone, and I started freaking out," Quichocho said. "He was just running back and forth stabbing people."

Quichocho said she ran to the second floor of the hotel with other guests to escape.

Guam Gov. Eddie Calvo issued a statement addressed to "the people of Japan" saying the perpetrator would be prosecuted "to the fullest extent of the law." Calvo said he would increase the police presence in the visitor district.

"This was an isolated incident -- something that just doesn't happen in our community," Calvo said. "We are shocked, we are grieving with the families, and we extend our deepest condolences to those hurt."

Guam, a U.S. territory and tropical island 1,500 miles south of Tokyo, is heavily dependent on tourism -- particularly from Japan -- for its economy.

The island has a population of about 180,000 and is home to major U.S. naval and air bases. The U.S. has plans to move several thousand Marines to Guam from the southern Japanese island of Okinawa.

WASHINGTON -- The United States and Japan announced on Thursday a revised agreement on streamlining the U.S. military presence on Okinawa that will shift 9,000 Marines from that southern Japanese island to Guam and other Asia-Pacific sites.

The new plan, unveiled days before Japanese Prime Minister Yoshihiko Noda visits President Barack Obama, helps the allies work around the still unresolved, core dispute over moving the Futenma air base from a crowded part of Okinawa to a new site that had vexed relations for years.

Under the agreement, 9,000 U.S. Marines will relocate off Okinawa: 5,000 to Guam and the rest to other locations such as Hawaii and Australia, U.S. officials said.

Issei Kato / Reuters, file

Hercules aircraft are parked on the tarmac at Marine Corps Air Station Futenma in Ginowan on Okinawa.

The updated version of a long-delayed 2006 plan "outlines an improved U.S. Marine Corps force posture in the Asia-Pacific, one that is more capable and one that is more geographically distributed," said a senior U.S. Defense Department official.

"This presence is integral to our larger strategy of rebalancing toward the Asia-Pacific," added the official.

Snags over Okinawa had raised questions about the viability of the Obama administration strategy of shifting U.S. forces from other regions to the Asia-Pacific to deal with nuclear saber-rattling by North Korea, the rapid military buildup of China and territorial disputes in the South China Sea.

Friction over U.S. bases intensified after the 1995 gang rape of a Japanese schoolgirl by U.S. servicemen. The case sparked widespread protests by Okinawans, who had long resented the American presence due to crime, noise and deadly accidents.

There are about 47,000 U.S. troops in Japan under a 1960 bilateral security treaty.

Okinawa, occupied by the United States from 1945-72, accounts for less than 1 percent of Japan's total land, but hosts three-quarters of the U.S. military facilities in the country in terms of land area.

"This has been ... bogged down for years, but now, we have been able to come up with a new approach delinking the Futenma relocation from other elements, like moving out Marine forces to Guam and returning some parts of Okinawa," said Ichiro Fujisaki, Japan's ambassador to the United States.

"Things are going to start moving," he told a gathering at a think tank in Washington.

Kurt Campbell, assistant secretary of state for East Asian and Pacific Affairs, said the deal was discussed widely with U.S. lawmakers, who had refused to fund the overhaul on Okinawa until the Futenma deadlock was resolved and the administration fully explained how the move would fit overall U.S. strategy.

"We think it breaks a very long stalemate ... that has plagued our politics, that has clogged both of our systems, that has made it difficult to deal with the critical and crucial issues that confront the United States and Japan and other countries in the Asia-Pacific," said Campbell.

'Rebalancing ' toward Asia-Pacific
"This is really a key component of our strategic rebalancing toward the Asia-Pacific region," a senior State Department official said.

"One of the key aspects of that is strengthening partnerships with regional allies. And, of course, Japan is a very important alliance partner," the official added.

The policy has also entailed closer U.S. military ties with The Philippines, Australia and Singapore

The agreement includes a $3.1 billion cash commitment from Japan for the move to Guam as well as for developing joint training ranges on Guam and on Tinian and Pagan in the Commonwealth of the Northern Mariana Islands.

The previous agreement on the move to Guam had Japan providing $6.09 billion in support, with $2.8 billion in cash and the rest in financing arrangements. Because of the smaller footprint the Marines will have in Guam, the two sides decided they no longer needed the loans but agreed to a Japanese cash contribution of $3.1 billion.

Campbell acknowledged that more work needed to be done, including eventually finding a replacement for Futenma.

Proposed replacement sites for Futenma on the subtropical island that lies between Japan's main islands and Taiwan have met strong local opposition while Tokyo was in political disarray, going through six prime ministers in six years.

"Does this agreement answer every question? It does not. Is there more programmatic and technical work that is necessary? Yes," said Campbell.

"But at a fundamental level, we think this agreement moves the ball very substantially down the field in a way that no one would have anticipated a few months ago," he said.

Separating the move to Guam from the nettlesome Futenma issue frees up the allies to work more on cyber security, space, intelligence, surveillance and reconnaissance operations and ballistic missile defense, the Pentagon official said.

That is "because we'd been spending so much time talking about the move from Futenma that we often were not making as much progress as we would have liked in other aspects of the alliance," the State Department official said.

Senators Carl Levin, John McCain and Jim Webb - top members of the Senate Armed Services Committee who had frozen Okinawa funding until their budgetary and strategic questions were answered - said some of their concerns were addressed.

"We still have many questions about the specific details of this statement and its implications for our force posture in the Asia-Pacific region," they said in a statement, which also vowed to keep working on "a mutually beneficial, militarily effective, and fiscally sustainable agreement" on Okinawa and Guam.

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