WASHINGTON (AP) -- Groups associated with al-Qaida are at the top of the list of threats to the United States, leading government intelligence officials said Wednesday, saying Iran has emerged as the top threat to American interests in the Middle East.

Despite gains made against al-Qaida, CIA Director Porter Goss, in an unusually blunt statement before the mostly secretive Senate Intelligence Committee, said the terror group is intent on finding ways to circumvent U.S. security enhancements to attack the homeland.

``It may be only a matter of time before al-Qaida or other groups attempt to use chemical, biological, radiological or nuclear weapons. We must focus on that,'' Goss said.

FBI Director Robert Mueller said he worries about a true sleeper operative whom he contended has been in place for years to launch an attack inside the United States. ``I remain very concerned about what we are not seeing,'' he said in his prepared remarks.

Mueller, Goss and other intelligence leaders provided these and other assessments at the annual briefing of threats from around the globe.

The head of the Defense Intelligence Agency, Vice Adm. Lowell Jacoby, painted Iran as a leading threat to U.S. interests in the Middle East.

In his prepared testimony, Jacoby said he believes that Iran will continue its support for terrorism and aid for insurgents in Iraq.

He said the country's long-term goal is to expel the United States from the region, and noted that political reform movements there have lost momentum.

In related developments:

• Defense Secretary Donald H. Rumsfeld also sent out a warning, telling the House Armed Services Committee he believes terrorists are regrouping for another strike. But he also said the United States is preparing to deal with any threat.

  ``The extremists continue to plot to attack again. They are at this moment recalibrating and reorganizing. And so are we,'' the Pentagon chief said.

• Secretary of State Condoleezza Rice plugged the administration's request for $5.8 billion to fight terrorism and also made a pitch on Capitol Hill for an additional $750 million this year for other countries that assisted in Afghanistan and Iraq.

In Iraq, Rice said the Senate Foreign Relations Committee, the United States wants to spend $360 million next year for economic assistance ``targeted toward helping the Iraqi government to create a functioning democracy and a justice system,'' among other services and improvements.

In the past year, the intelligence community has been faced with a series of negative reports, including the work of the Sept. 11 commission and the Senate Intelligence Committee's inquiry on the flawed Iraq intelligence.

And next month, President Bush's commission to investigate the intelligence community's capabilities on weapons of mass destruction is also expected to submit its findings.

Given the after-the-fact investigations into the Iraq intelligence, Senate Intelligence Chairman Pat Roberts, R-Kansas, said his panel will become more proactive in how it reviews the intelligence community's strengths and weaknesses, already focusing on nuclear terrorism and Iran.

The hearing came as the White House continues its eight-week-long search for a new national intelligence director, a position created in last year's intelligence reorganization bill.

Democrats were critical Wednesday of the pace of the search, saying the administration has not shown the same urgency that Congress showed in creating the position.

``There should be another chair before us, with an accompanying name card that reads director of national intelligence,'' said Sen. Jay Rockefeller of West Virginia, the panel's ranking Democrat.

Roberts said it was ``crucially important'' to get the right person.

The hearing marked the first public appearance for Goss, the former House Intelligence Committee chairman, since his confirmation hearing in September.

Critics say he's politicizing the agency by surrounding himself with Republican advisers from his years in Congress. Yet his allies say he's promoting agency veterans to senior management positions and making changes essential to ensure the intelligence community does not repeat the kind of blunders that led up to the Sept. 11, 2001 terror attacks and the faulty prewar estimates of Iraq's weapons.