'Al Qaeda still biggest threat'

Porter Goss, the new chief of the Central Intelligence Agency (CIA) has said that although it had been weakened by intensified US and international operations, the al Qaeda remains the top threat to the United States.

"It may be only a matter of time before al Qaeda or other groups attempt to use chemical, biological, radiological or nuclear weapons. We must focus on that," Goss told a Senate Intelligence Committee hearing Wednesday.

Aggressive measures taken by US law enforcement, defense and

homeland security community along with international partners have "dealt serious blows" to the al Qaeda, but the terrorist group is still intent on finding ways to attack US targets in the homeland and abroad.

While the US is pursuing al Qaeda's most senior leaders, their capture of them "will not be enough to eliminate the terrorist threat," he said.

Federal Bureau of Investigation Director Robert Mueller expressed concern that a sleeper operative in place for years might launch an attack inside the United States.