Al Qaeda is certain to mount another attack on the US in the next three to six months and will continue to target the nation until Osama-bin Laden and his deputy are "killed or captured," according to top US intelligence officials.
"The chances of an attempted attack are certain. They are going to try," CIA chief Leon Panetta said deposing before the Senate Intelligence Committee.
Panetta said bin Laden had "deployed individuals to this country, who continue to stay in touch with the group".
Panetta deposed before the committee along with Dennis Blair, chief of National Intelligence, FBI Director Robert Mueller and Chairman Chief of Staff Admiral Mike Mullen. All of them warned about a "lone-wolf attacker".
"I think its lone wolf plan, which I think we have to pay the highest attention to, would form the greatest threat to the country," Panetta said.
Blair told the committee that Al Qaeda was maintaining its intent to attack the US with a large-scale operation to cause mass casualties, harm the US economy or both.
Their depositions and warnings about continued terror threats came as a bipartisan group of top senators on Wednesday introduced legislation in the Senate to cut off funding for the trials of the 9/11 conspirators in civilian court and support their trials by a military commission.
22 senators, including Republican Lindsey Graham, moved the bill. "I believe it is inappropriate to give the mastermind of 9/11 the same constitutional rights as an American citizen," Graham said.
"It has never been done in the history of warfare and now is not the time to start. Military Commissions are proper venue for the trial of Khaled Sheikh Muhammad and other 9/11 conspirators," he argued.
Elaborating on the intelligence inputs on Al Qaeda, Blair said: "We assess that at least until Osama bin Laden and Ayman al Zawahiri are dead or captured, al Qaeda will retain its resolute intent to strike the homeland".
The national Intelligence Chief said US investigators would like to capture bin Laden alive and squeeze him of information.
Blair said the threat from Al Qaeda was evolving and it has been evident in attacks carried out by Najibullah Zazi, Umar Farouk Abdulmutallab and Maj Nidal Hasan.
Mueller said over the past decade, the focus of strategic terrorism threats has been South Asia, but the threat has been shifting to the Arabian Peninsula of late.
"This evolution has been most rapid with Al Qaeda in the Arabian Peninsula which has changed from a regional group with links to Al Qaeda to a global threat with reach into American cities such as Detroit," he said.
Lt Gen Ronald L Burgess, Director Defence Intelligence Agency, said Al Qaeda remains the most significant terrorist threat to the US and the group still pursues chemical, biological, radiological or nuclear materials for attacks.
Meanwhile, supporting the trials of 9/11 conspirators by a military commission were Senators John McCain, Jim Webb, Joe Lieberman, Jeff Sessions, Blanche Lincoln, Orrin Hatch, Saxby Chambliss, and John Barrasso.
"Civilian trials, which the Obama Administration has proposed, will be unnecessarily dangerous, legally messy, confusing to our own troops who fight and capture terrorists on the battlefield, and very expensive," Graham said.
Judiciary Committee ranking member Senator Sessions said: "Simply moving the 9/11 trials from New York City is not a solution. As long as these trials are in civilian court they will bring severe costs and dangers with them wherever they go".
Believing that conducting military tribunals is the most effective means to accomplish that goal in these cases, Senator Lincoln said trying these conspirators in civilian courts is giving them a public stage to advocate their cause.