From [1] This Is London:

The threat of a terrorist attack using nuclear weapons is "real and imminent", the head of the UN's nuclear watchdog said today.

Mohammed al Baradei, chief of the International Atomic Energy Agency, said it was a "race against time" to prevent terrorists from obtaining nuclear materials. ...

"We are actually having a race against time which I don't think we can afford," he told the Carnegie Endowment for International Peace conference in Washington. "The danger is so imminent... so the sooner that we start, the better for everybody involved."