Alert highlights 'dirty bomb' fears

Nuclear fuel rods can be used in 'dirty bombs'

By BBC News Online's Nick Caistor

The White House is concerned that Osama Bin Laden may have radioactive material that could be used to make a "dirty bomb", press reports in the United States suggest.

Tom Ridge, director of homeland security, issued a new security alert this week, the third since the 11 September attacks for which the US blames Bin Laden.

Mr Ridge denied that his warning on Tuesday was related to any specific threat, but the Washington Post newspaper reported that intelligence sources are increasingly worried at the possibility that Bin Laden's al-Qaeda network could explode a radioactive device.

'Dirty bombs' could be used by Bin Laden's group

A "dirty bomb" involves wrapping radioactive material such as spent nuclear fuel rods around ordinary high explosives, and detonating the device.

The package could be used in a car bomb or many other forms of delivery. The damage is not caused so much by the explosion, but by the intense radiation that would be released into the atmosphere.

This could cause deaths, and cancers and other health problems over many years, as after the nuclear accident at the Chernobyl plant in the Ukraine.

There are also fears that a terrorist group could hijack a plane and crash it into a nuclear power station.

'Deterrent' claims

In October, Bin Laden, the main suspect in the 11 September attacks on America, told a Pakistani newspaper his group possessed chemical and nuclear weapons.

We cannot exclude the possibility that Bin Laden's group could get hold of this material to make a radioactive weapon

David Kyd, IAEA

The Dawn newspaper quoted Bin Laden as saying: "If America used chemical and nuclear weapons against us, then we may retort with chemical and nuclear weapons. We have the weapons as a deterrent."

More recently, the US confirmed documents found in a building in Kabul believed to have been used as a safe house by al-Qaeda fighters contained instructions on how to build a nuclear device.

US special forces who raided former al-Qaeda facilities in Afghanistan also spoke of evidence that they were planning to create weapons of mass destruction, including nuclear devices.

While intelligence sources consider al-Qaeda does not have the capability for building a fully-fledged nuclear device, a "dirty bomb" is a more feasible alternative.

Possible sources for spent uranium or plutonium could be Pakistan or former Soviet republics.

David Kyd, a spokesman for the UN's International Atomic Energy Agency, told the BBC that there were some 175 cases of seizure of nuclear material being smuggled from former Soviet republics.

"We cannot exclude the possibility that Bin Laden's group could get hold of this material to make a radioactive weapon rather than buying a nuclear weapon off the shelf or making one themselves," he said.

Pakistan says its nuclear materials are "in safe hands"

Pakistan has insisted that its nuclear assets are in safe hands.

John Large, an independent nuclear consultant, also says Pakistan is an unlikely source.

"Pakistan has an early nuclear programme and its highly-enriched uranium would be very precious to it. It would not have enough to spare, even if it wanted to", he says.

Robbery threat

But the IAEA warned recently that security and regulation of nuclear material in the former Soviet Union is poor.

The agency's director, Mohamed ElBaradei, said "the prospect of nuclear terrorism has been catapulted to the forefront," and called for increased international efforts to reduce the risks of nuclear smuggling.

Security has been stepped up at US nuclear plants

A report in the Washington Post newspaper quoted a Russian general as saying that unidentified terrorists had recently twice tried and failed to penetrate Russian nuclear storage facilities.

At the end of November, the United States announced it would provide the IAEA with an additional $1.2 million to strengthen protection of nuclear and radioactive materials.

Announcing the new state of alert on Tuesday, Mr Ridge insisted he had no idea how any terrorist attack might come, but said the level of reported threats had increased considerably in recent days.