U.S. intelligence officials say Islamic militants along with Iran and North Korea are the top threats facing the United States. They offered their assessments at a public hearing before a Senate panel Wednesday, as correspondent Deborah Tate reports from Capitol Hill.

Central Intelligence Agency Director Porter Goss says despite gains made by the United States and its allies in cracking down on al-Qaida, the terrorist network blamed for the September 11, 2001 attacks on New York and Washington remains a threat to the United States.

In testimony before the Senate Intelligence Committee, Mr. Goss said it may be a matter of time before al-Qaida or other groups linked to the network attempt to use chemical, biological, radiological or nuclear weapons.

He also warned of the threat posed by insurgents fighting U.S.-led forces in Iraq:

"Islamic extremists are exploiting the Iraqi conflict to recruit new anti- U.S. jihadists. Those jihadists who survive will leave Iraq experienced and focused on acts of urban terrorism. They represent a potential pool of contacts to build transnational terror cells and networks in Saudi Arabia, Jordan and other countries."

The Director of the Federal Bureau of Investigation, Robert Mueller, expressed concern about the possibility of al-Qaida operatives in the United States who could launch an attack on U.S. soil.

"Finding them is the top priority for the FBI, but it is also one of our most difficult challenges."

Besides terrorist groups, CIA Director Goss said North Korea and Iran posed key threats to the United States.

A week after North Korea said for the first time that it has nuclear weapons, Mr. Goss highlighted his concern about Pyongyang's missile capability.

"North Korea could resume flight testing at any time, including longer range missiles, such as the Taepo Dong Two system. We assess the TD-Two is capable of reaching the United States with a nuclear weapon-sized payload."

Mr. Goss said Iran remains a state sponsor of terrorism. He said Tehran is stepping up efforts to build long range ballistic missiles and is refusing to give up its ability to produce enriched uranium that could be used in nuclear weapons development.

Mr. Goss also said Iran is supporting what he called "anti-coalition activities" in Iraq in an effort to, as he put it, "influence the future character of the Iraqi state."

It was Mr. Goss' first public appearance before Congress as CIA Director. The former congressman and House Intelligence Committee chairman took charge of the agency last year.