Updated at 8:15 a.m. ET: Afghan security forces on Saturday arrested five insurgents suspected of planning massive attacks on crowded areas of the capital Kabul, an intelligence spokesman said.

National Directorate of Security (NDS) spokesman Shafiqullah Tahiri said the five men were seized on Kabul's outskirts with 10,000 kilograms of explosives (11 tons) stuffed in 400 bags and hidden beneath a cargo of potatoes in the back of a Pakistan-registered truck.

The group also planned to assassinate the country's second vice-president Abdul Karim Khalili, the BBC reported.

---

The BBC's Bilal Sarwary reported on Twitter that a video detailing the insurgents' plan had been found.

"It could have caused large-scale bloodshed," Tahiri told a news conference in Kabul.

"Three Pakistani terrorists and two of their Afghan collaborators who placed the explosives under bags of potatoes in a truck were caught."

Tahiri said the five men confessed to receiving training from Noor Afzal and Mohammad Omar, whom he identified as key commanders of the Pakistani Taliban and Pakistan intelligence.

Video footage released by NDS to media showed the detained men, including the alleged Pakistanis, talking about where they came from while sitting against a blank white wall.

A Pakistani intelligence official declined comment on the accusations, while Afghan officials were not immediately available to give additional information.

Coordinated assault
The alleged connection to militants in Pakistan will likely step up the pressure on Islamabad, after a recent assault by insurgents on diplomatic and government areas in Kabul and elsewhere put the spotlight on the South Asian nation. 

Afghan officials have long accused Pakistan of using insurgent groups like the Afghan Taliban as proxies in Afghanistan. 

Pakistan's government denies supporting or giving sanctuary to insurgents on its territory. 

Insurgents this week launched a coordinated assault on four provinces, targeting diplomatic and government areas of Kabul with rockets and gunfire in what they said was retaliation for abuses of Afghans by U.S. soldiers.

Kabul fighting ends after 18 hours of intense gunfire

The attacks showed the insurgency's resilience nearly 11 years since the Afghan Taliban were toppled.

The Afghan Taliban claimed responsibility for the attacks and said it planned similar assaults in coming months.

Reuters contributed to this report.

LONDON -- A Russian former banker was in a critical condition and under armed guard in hospital on Monday after surviving an assassination attempt outside his luxury apartment in London's financial district.

German Gorbuntsov, 45, who at the height of his business empire owned four Russian banks, was walking toward his upscale apartment block in the Canary Wharf area when a gunman shot him five times on Tuesday.

---

The gunman escaped on foot, The Telegraph newspaper reported.

Police said they were searching for a taxi driver who let Gorbuntsov out moments before the 7:30 p.m. attack, according to the newspaper. 

Coma
Gorbuntsov's lawyer, Vadim Vedenin, told Reuters his client remained in a medically induced coma to give him a chance to recover, and that doctors were hoping to revive him in about three days.

Vedenin said that Gorbuntsov had been days away from giving evidence to an investigation into the attempted murder of a former business associate, Alexander Antonov, in 2009.

"He was preparing to give evidence on certain people. He has already given it in written form and he was going to do so in official testimony," Vedenin said by phone, adding that Gorbuntsov had come to London because he feared for his life.

Frantic shouting
London police said on Saturday they were keeping an open mind about the motive of the attack outside the apartment block. A member of the building's staff, who declined to give his name, said he heard no shots, but ran outside when he heard frantic shouting.

"He is a customer here. He was still alive. He spoke to us in Russian. I understood what he was saying," the member of staff, a Polish man, told Reuters. "He was swearing a lot."

London is home to thousands of Russian business people seeking capital, prestige and, in many cases, a haven from the rough and tumble of their home country's financial world.

Cash-for-access scandal leaves UK government reeling

Antonov made his career in the nuclear industry, then became its banker as owner of Konversbank, a financial institution founded to serve the nuclear industry about two decades ago.

Antonov said he and Gorbuntsov had disagreed over the terms of a bank sale just before the debt crisis of 2008, but that there had been no acrimony.

"Our relationship is friendly, and it has always been friendly," he told Reuters. "I have a great personal interest in his testimony."

The attempt on his life in 2009 was linked in Russia to the 2008 murder in Moscow of Ruslan Yamadayev, a powerful opponent of the Kremlin-backed Chechen leader Ramzan Kadyrov.

The two incidents were tried as a single case and three men were convicted. But the person or persons who ordered the murders was never identified, and the case had lain dormant until this year.

Spy case
Diplomatic relations between Russia and Britain have been tested by a series of disputes involving Russian emigres.

Russia has refused to extradite the man suspected of murdering former Russian spy Alexander Litvinenko by putting radioactive polonium in his tea in London.

Meanwhile, London courts have refused to extradite men wanted in Russia, including the Russian tycoon Boris Berezovsky, a former Kremlin insider turned fierce critic with criminal convictions in Russia.

Berezovsky, who says the charges brought against him in Russia are politically motivated, told Reuters by telephone from London that he did not know Gorbuntsov personally, nor did he know of any Russian criminals hiding out in London.

"One can give differing views, but it is important to understand that ... there is no place safer than London from Kremlin bandits or from Russian or international criminals," he told Reuters. "But that of course is no guarantee they won't get you."

Msnbc.com staff and Reuters contributed to this report.

More from msnbc.com and NBC News:

• Wife of Staff Sgt. Bales: 'I just don't think he was involved'
• Scientists: Venice sinking five times faster than thought
• Gunman in Afghan army uniform kills 2 NATO troops
• Simon Cowell finds intruder in his bathroom
• Cash-for-access scandal leaves UK government reeling
• Retired Turkish general faces terrorism trial
• Transgender candidate booted from Miss Universe Canada

Follow us on Twitter: @msnbc_world

Story updated 3 a.m. ET:

The Obama administration denied any role in the assassination on Wednesday of an Iranian nuclear scientist, in response to suspicion that Israel or the United States were involved in the attack - and similar previous incidents.

Nuclear scientist Mostafa Ahmadi Roshan, 32, was killed Wednesday by a magnetic bomb reportedly attached to his car by two assailants on a motorcycle in traffic. The cars of three other Iranian scientists, at least two of whom were working on nuclear activities, were blown up in 2010 and 2011 in similar circumstances.

---

Iran, and many analysts in the region, suspect outside involvement in the incidents.

"Instead of actually fighting a conventional war, Western powers and their allies appear to be relying on covert war tactics to try to delay and degrade Iran's nuclear advancement," said Theodore Karasik, a security expert at the Dubai-based Institute for Near East and Gulf Military Analysis.

But the U.S. has insisted it had nothing to do with Wednesday's killing.

Iranian Vice President Mohammad Reza Rahimi, in charge while President Mahmoud Ahmadinejad travels in Latin America, told state television that "this terrorist act was carried out by agents of the Zionist regime (Israel) and by those who claim to be combating terrorism (the United States) with the aim of stopping our scientists from serving" Iran.

He said Iran's nuclear program would go on.

Iran has said it is developing nuclear capabilities only for energy and other peaceful purposes, but the United States and its allies accuse it of wanting to create a nuclear weapon. Four rounds of sanctions have been imposed on Iran. On Jan. 23, European Union foreign ministers plan to discuss a possible oil export embargo, adding further pressure.

Iran urged the U.N. Security Council and Secretary-General Ban Ki-moon to condemn the assassinations of scientists, calling the killings "cruel, inhumane and criminal acts of terrorism." Iran's U.N. Ambassador Mohammad Khazaee appealed to Ban and the 15-nation council, "Any kind of political and economic pressures or terrorist attacks targeting the Iranian nuclear scientists, could not prevent our nation in exercising this right" to pursue its nuclear program, Khazaee said in a letter obtained by Reuters.

'Unnatural' happenings
The Obama administration denied any U.S. involvement. Israel did not deny involvement, and there are hints that the Jewish state at least had advance knowledge. 

The Associated Press reported that  Lt. Gen. Benny Gantz told a closed meeting of Israel's Foreign Affairs and Defense Committee on Tuesday that "2012 is expected to be a critical year for Iran." He cited "the confluence of efforts to advance the nuclear program, internal leadership changes, continued international pressure and things that happen to it unnaturally."

Gantz's testimony was leaked by a meeting participant who spoke on condition of anonymity.

On Wednesday, Israel's chief military spokesman, Brig. Gen. Yoav Mordechai, posted on Facebook: "I don't know who settled the score with the Iranian scientist, but I certainly am not shedding a tear," according to a Reuters report.

Hazhir Teimourian, an Iran expert at the Limehouse Group of Analysts in London, stressed to Reuters that it was impossible to be certain who carried out the attack. But he said Israel was a logical candidate.

"The Israelis really have the ability and the incentive," he said.

List of attacks
Iran has accused the Mossad, the CIA and Britain's spy agency of engaging in an underground campaign against nuclear-related targets, including at least four killings since early 2007. They include:

• In January 2010, a physics professor, Massoud Ali Mohammadi, was killed by a bomb in a motorcycle that blew up near his car as he left his Tehran home for work.
• In November 2010, scientist Majid Shahriari, who managed a "major project" for Iran's Atomic Energy Organization was killed and colleague Fereydoon Abbasi, on the U.N. Security Council’s sanctions list for ties to the Iranian nuclear effort, was wounded when motorcyclists attached magnetized bombs to their cars in separate parts of Tehran.
• In July 2011, Darioush Rezaeinejad, who allegedly was working on a nuclear detonator, was shot in the neck outside his daughter's Tehran kindergarten.
• In 2007, nuclear scientist Ardeshir Hosseinpour died of gas poisoning.

Another key attack was the release of a malicious computer virus known as Stuxnet in 2010 that temporarily disrupted controls of some Iranian centrifuges — a key component in nuclear fuel production.

Ronen Bergman, an investigative journalist with the Yediot Ahronot daily and expert on Israeli intelligence affairs, said the Mossad has "for years" targeted enemies that include "nuclear proliferators."

"The outcome of such assassinations are the actual neutralization of the main scientists and the intimidation of those left behind," he said.

Israel measures the gains in terms of the delays they cause Iranians.

"They are not keeping to the schedules they would like to keep to," former Mossad spymaster Meir Dagan said in a recent television interview, smilingly crediting the apparent sabotage spree to "God, who controls everything."

It also provokes panic in surviving colleagues, said an Israel official, generating a phenomenon that Mossad veterans dub "virtual defection."

"It's not that we've been seeing mass resignations, but rather a sense of spreading paranoia given the degree to which their security has been compromised," the official, who has extensive Iran expertise, told Reuters.

"It means they have to take more precautions, including, perhaps, being a little less keen to stand out for excellence in their nuclear work. That slows things down."

Israeli attacks
Israel has an admitted history of state-sponsored assassination and intimidation, from letter-bombs it sent German scientists serving Egypt's missile program in the 1960s to the Mossad hunt, using guns and booby-traps, for Palestinians involved in killing 11 Israeli athletes at the 1972 Olympics.

More recently, Israeli air-launched missiles and special forces picked off Palestinian uprising leaders. In 1995, motorbike-borne gunmen killed Islamic Jihad chief Fathi Shiqaqi in Malta, and another suspected Mossad team smothered Hamas commander Mahmoud al-Mabhouh in his Dubai hotel in 2010.

Proponents of such tactics say they stave off more ruinous open war and few voices are raised in Israel in condemnation. Mabhouh had helped smuggle rockets to Palestinians, a threat Israel cited in justifying its 2008-2009 offensive on the Gaza Strip, amid international outcry at the high civilian toll.

Also on Wednesday:

Clinton cites danger: Secretary of State Hillary Rodham Clinton, reiterating that the U.S. played no role in the killing of Roshan, said the United States is looking for an international understanding with Iran that ends its uranium enrichment program.called recent Iranian threats to close off the Persian Gulf "provocative and dangerous." She said the U.S. was committed to keeping the international waterway open. She called it "part of the lifeline that keeps oil and gas moving around the world." About 35 percent of the world's seaborne traded oil passes through the Strait of Hormuz. 

Slammed at the U.N.: France, Britain, Germany and the United States on Wednesday took advantage of a closed-door meeting of the U.N. Security Council to condemn Iran's decision to begin enriching uranium at an underground bunker. "It's a worrying development," French Deputy Ambassador Martin Briens told reporters. He added that Tehran's new move was a violation of multiple resolutions of the U.N. Security Council and the International Atomic Energy Agency's board of governors. "We see this as a step of escalation by ... Iran," Deputy German Ambassador Miguel Berger said.

Cuba visit: Iranian President Mahmoud Ahmadinejad arrived in Havana for a one-day visit. Reuters reported that Ahmadinejad was greeted by one of Cuba's vice presidents, Esteban Lazo, and was driven away in a black Mercedes ahead of a meeting with President Raul Castro. Cuba was his third stop on a Latin American tour meant to show support from four leftist-led nations - Venezuela, Nicaragua, Cuba and Ecuador -- as Iran is increasingly isolated by tightening Western economic sanctions over its uclear program.

Reuters, The Associated Press, The New York Times and msnbc.com's Jim Gold contributed to this article.

More from msnbc.com and NBC News:

• Divided opposition bolsters defiant Assad
• Iran's Ahmadinejad talks tough against US during Latin America tour
• French journalist killed in Syria
• Chinese applications to U.S. schools skyrocket
• 'Tortured' Gitmo prisoner seeks release of secret videos
• Three million parade in Philippines despite terror threat
• US expels diplomat after cyber-attack allegations
• Kremlin's photo-doctoring backfires big time
• Divided opposition bolsters defiant Assad