The UN's nuclear watchdog warned today that so-called dirty bombs pose a greater threat than ever as long as attackers are willing to kill themselves.
Mr Mohammed El Baradei, head of the International Atomic Energy Agency (IAEA), said at the opening of a three-day conference in Vienna, Austria, that radiological weapons were harder to stop if those using them had no fear for their own safety.
"Given the apparent readiness of terrorists to disregard their own safety, the personal danger from handling powerful radioactive sources can no longer be seen as an effective deterrent," he said.
"Much remains to be done to improve the security of radioactive sources worldwide," Mr El Baradei said.
Dirty bombs consist of radioactive material set off by conventional explosives, and experts say that although they are less lethal than nuclear weapons, they can inflict widespread disruption for relatively little cost.
Mr El Baradei warned last year that the materials to make a dirty bomb were available across the globe and called for stepped-up security to keep them from falling into the wrong hands.
Around 600 delegates are attending the conference, which is being sponsored by the IAEA, the United States and Russia.
AFP