CIA Director Porter Goss (L) and FBI Director Robert Mueller (R) address a Senate hearing on intelligence on Capitol Hill in Washington, DC. (AFP)

    WASHINGTON, Feb. 16 (Xinhuanet) -- The new chief of the Central Intelligence Agency (CIA) warned Wednesday that al Qaeda remains the top threat to the homeland security of the United States, although it had been weakened by intensified US and international operations.

    "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," Porter Goss told a Senate Intelligence Committee hearing.

    Goss said aggressive measures taken by US law enforcement, defense and homeland security community along with international partners have "dealt serious blows" to al Qaeda and other terrorist organizations and individuals.

    But the terrorist group is still intent on finding ways to attack US targets in the homeland and abroad. He said the United States is pursuing al Qaeda's most senior leaders, but the capture of them "will not be enough to eliminate the terrorist threat.

    Federal Bureau of Investigation Director Robert Mueller said he remained very concerned that a sleeper operative in place for years might launch an attack inside the United States. Enditem