"Unfortunately, some of these devices are still located on American soil," said Stanislav Lunev.
Lunev is a former Soviet military intelligence officer, a defector who's now in the federal witness protection program. He claims that before the Cold War ended a decade ago, Soviet agents planted so-called "suitcase nuclear bombs" in the United States and other Western countries nuclear bombs that could be triggered if war broke out.
"They were designed to destroy extremely highly protected American targets," he said.
Lunev, his identity protected, told the same story to Congress and a former Soviet general told CBS's 60 Minutes that the suitcase bombs existed.
But, reports CBS News Correspondent Jerry Bowen, many U.S. defense analysts are convinced Russia actually retrieved and dismantled all the small nuclear devices.
"Our view is that it is not a major worry. If those devices ever existed, they were under the control of the Soviet state, and not available to terrorists," said Michael O'Hanlon of the Brookings Institution.
But the Soviets weren't the only ones to create a so-called suitcase nuke. A recently declassified film shows how the United States had them in its arsenal in the early '60s. Defense experts dismiss the possibility that terrorists can build one themselves.
"To do something like that in the mountains of Afghanistan would be extremely difficult," said John Lepingwell of the Center For Nonproliferation Studies.
But four years ago, bin Laden was named in a federal indictment for attempting to buy enriched uranium nuclear material which experts say could be put in a conventional explosive.
"But it's very difficult to get that much radioactive material into the bomb and disperse it in such a way as to cause major casualties," explained Lepingwell.
But might bin Laden have gotten some larger nuclear warheads?
"I know from intelligence information that he has obtained several devices from former Soviet Union, technical nuclear devices," said Lunev
Reports like this are unsubstantiated, and whether al-Qaida could handle and smuggle such things is thought to be highly improbable. Still, U.S. Customs agents are training border guards from countries surrounding Afghanistan to detect nuclear material one more small front in a very different kind of war where nothing is being taken for granted.
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