From the Associated Press:
LONDON, England -- There is a "very high" probability that a terrorist group will strike using nuclear, chemical or biological weapons, a senior U.S. counterterrorism official said in comments published Tuesday.
"I rate the probability of terror groups using (weapons of mass destruction) as very high," U.S. State Department counterterrorism coordinator Henry Crumpton was quoted as saying by the Daily Telegraph newspaper. "It is simply a question of time."
Crumpton said a biological attack was potentially the most troubling scenario. He said evidence from Afghanistan suggested al-Qaeda had been seeking to develop anthrax before the overthrow of the Taliban regime in 2001.
"It is not just the nuclear threat that bothers me," he was quoted as saying. "I think, if anything, the biological threat is going to grow."
"As catastrophic as a nuclear attack would be, it would be self-contained. But if you look at a worst-case scenario for a biological attack, it would be difficult to determine whether or not it was a terrorist attack, and it would be far more difficult to contain."
Crumpton told the newspaper that U.S. and international efforts had severely disrupted the al-Qaeda network since the September 11, 2001, attacks in the United States, but that "in all probability" Osama bin Laden was still alive.