Dirty bomb attack 'pretty likely' despite nuclear deal

A landmark summit of world leaders in Washington has agreed to secure vulnerable nuclear materials around the globe within four years. The pledge came in a final communique issued after summit host US president Barack Obama warned that nuclear material the "size of an apple" would be enough to kill thousands of people if it fell into the hands of terrorists. Tilman Ruff, Associate Professor at Melbourne University and chair of the International Campaign to Demolish Nuclear Weapons, says the possibility of terrorists getting hold of radioactive material and attaching it to a conventional explosive is highly likely. "Detonating it in a major city is the simplest and most likely form of nuclear terrorism. I think ... it's pretty likely that somewhere we'll see such an episode."

"These materials are still unfortunately widely available in thousands of locations. [But] the possibility of terrorists building a nuclear weapon will no doubt be diminished by the kind of work that this summit has accelerated." Professor Ruff says the damage such an attack could cause would be severe. "It wouldn't be a nuclear explosion, so it might kill immediately hundreds or thousands of people in a crowded city, rather than tens or hundreds of thousands even a relatively small nuclear weapon would," he said. "But it would contaminate potentially several square kilometres, for example, of a major city centre.