Experts expect CBRN attack on U.S. within six months

Another attack on the U.S. by Al Qaeda within the next three to six months is expected, top U.S. intelligence officials have said, noting that the terror organization has been pursuing chemical and biological options.

According to Lt. Gen. Randal Burgess, the director of the Defense Intelligence Agency, Al Qaeda is the most significant threat to the United States and has routinely sought out biological, chemical, radiological and nuclear materials for attacks.

In a deposition before the Senate Intelligence Committee, CIA chief Leon Panetta noted that, "The chances of an attempted attack are certain. They are going to try."

Panetta added that Osama bin Laden has "deployed individuals to this country who continue to stay in touch with the group."

Dennis Blair, director of National intelligence, told the same committee that Al Qaeda's intent is to create a large scale operation that will inflict mass casualties, harm the U.S. economy or both.

Blair told the committee that the the so-called lone wolf attacker called for the most urgent attention, noting that a single person acting alone posed the greatest threat to the nation.

"I think its lone wolf plan which I think we have to pay the highest attention to as this would form the greatest threat to the country," Panetta said.