Updated

Top intelligence and military officials say the lack of attacks in the United States since 2001 does not mean terrorist groups are not planning new strikes, with weapons of mass destruction (search) if they can get them.

Defense Secretary Donald H. Rumsfeld (search) told a House hearing on Wednesday that it is reasonable to expect attacks and CIA Director Porter Goss (search) told the Senate Intelligence Committee the Iraq war was giving terrorists experience and contacts for future attacks.

FBI Director Robert Mueller said a sleeper group may have been in place in the United States for years awaiting orders to attack.

"I remain very concerned about what we are not seeing," Mueller said.

Rumsfeld told the House Armed Services Committee that the proposed $419 billion defense package for 2006 would set an ambitious course to "continue prosecuting the war and to attack its ideological underpinnings."

The current congressional debate over how to allocate billions of dollars on initiatives aimed at spreading peace and ensuring security follows three years of massive spending in response to the attacks of Sept. 11, 2001.

Goss said al-Qaida remains intent on circumventing U.S. security measures and attacking the United States.

"It may be only a matter of time before al-Qaida or other groups attempt to use chemical, biological, radiological or nuclear weapons," Goss said at the Senate Intelligence Committee's annual hearing on threats.

"Those jihadists who survive will leave Iraq experienced in and focused on acts of urban terrorism. They represent a potential pool of contacts to build transnational terrorist cells, groups and networks," Goss said.

Goss said North Korea continues to "develop, produce, deploy and sell ballistic missiles of increasing range and sophistication." He said the secretive regime could "at any time" resume flight testing of a long-range missile capable of reaching the United States with a nuclear payload.

Iran, too, is further improving its Shahab-3 long-range ballistic missile, which has a range of more than 800 miles, Goss said.

In written testimony, Vice Adm. Lowell Jacoby, director of the Defense Intelligence Agency, said he believes Iran will continue its support for terrorism and aid for insurgents in Iraq. "Iran's long-term goal is to see the U.S. leave Iraq and the region," he said.

Speaking to the Senate Foreign Relations Committee, Secretary of State Condoleezza Rice blamed Syria for having undermined stability in neighboring Lebanon. On Monday, a massive car bomb explosion in downtown Beirut killed former Lebanese Prime Minister Rafik Hariri.

"The Syrians (have) a special responsibility for the kind of destabilization that happened there, that this sort of thing could happen," said Rice, who also blamed Syria for contributing to the insurgency in Iraq and endangering U.S. forces.

Rumsfeld cited U.S. success in building a 90-nation anti-terror coalition, but cautioned: "It isn't over. It's going to take a while. It is a very serious business we're in."