Western governments have come under fire for doing little to end the easy availability of ingredients for making weapons of mass destruction.
A report funded by an anti-proliferation watchdog on Tuesday said 'only a tiny fraction' of a total $20 billion pledged by the Group of Eight last year to secure the stockpiles of nuclear, chemical and biological materials has been spent or even allocated to specific projects.
"The threat is outpacing the response," said Sam Nunn, former US senator and head of the watchdog, Nuclear Threat Initiative.
Nunn said the war in Iraq had distracted the US and diverted resources away from the need to secure weapons of mass destruction materials in regions such as the former Soviet Union.
"We have spent more now on the war than it would take to lock up all the nuclear materials around the globe," Nunn said.
The report pointed out that there are some 100 poorly protected research reactors, spread across 40 countries, containing weapons-usable uranium.
"We've spent more now on the war than it would take to lock up all the nuclear materials around the globe"
head of Nuclear Threat Initiative
"To construct a nuclear bomb, terrorists would need to steal only a small amount of nuclear material, about enough to fit in a suitcase," the report said.
Nunn said "terror-groups" were more likely to acquire weapons of mass destruction from ill-secured research sites than a country that has spent years in developing its weapons.
"Theft or sale of nuclear material from these stockpiles is more likely source of supply," he said.
The watchdog chief said the pace of securing the stockpile sites was too slow.
"At the pace we are going, you are talking about 20 years. I donâ€™t think we have got that long," he argued.