ASHINGTON, May 19 — Vice President Dick Cheney said today that he considered another major attack by Al Qaeda against the United States to be "almost certain."
Mr. Cheney and Condoleezza Rice, the national security adviser, said in separate appearances on television news programs that they had no specific information about the expected timing or location of any attacks. But they added that worldwide surveillance of Al Qaeda messages and other intelligence confirmed the terrorist network's continued interest in attacking American targets.
The confirmation by senior administration officials of continuing threats against targets here comes as Congress is debating how to investigate the handling of similar intelligence before Sept. 11.
Representative Richard A. Gephardt, the House minority leader, appeared today to soften his earlier insistence that there be an independent investigation, separate from the joint inquiry by the House and Senate intelligence committees. "I think the investigation that's going on is a good one," he said on "Fox News Sunday." He added: "We might want to look at adding to that an investigation that includes outsiders so that we can get this information out sooner." When pressed on whether he wanted public hearings, he said, "I'm not sure you need public hearings."
In his appearances, Mr. Cheney ruled out releasing the full text of a report from a Federal Bureau of Investigation field office in Phoenix warning that Al Qaeda operatives were training at flight schools in the United States. He added, however, that the document was "fair game" for a Congressional committee that would keep it secret.
He also said a decision by President Saddam Hussein of Iraq to allow international weapons inspectors back into Iraq would not satisfy United States concerns about Baghdad's development of weapons of mass destruction.
On the NBC program "Meet the Press," Mr. Cheney said that "the prospects of a future attack against the United States are almost certain."
"We don't know if it's going to be tomorrow or next week or next year," he continued. "But the prospect of another attack against the United States is very, very real." He said it was "just as real, in my opinion, as it was Sept. 12."
Mr. Cheney did not portray the information as new but said it was "a reminder that we're still very heavily engaged in this war on terror." He used similar language on "Fox News Sunday."
Ms. Rice, appearing on the CBS program "Face the Nation," said the volume of such reports might have grown, but that was largely because United States and foreign intelligence agencies had heightened mobilization and cooperation since Sept. 11.
Given the tougher security precautions initiated since September at airports and other ports of entry, Ms. Rice said, there was no need to ratchet up security measures in response to any recent threats.
"This is not a new set of warnings," she said. She added that from time to time, the amount of information "will spike," but the crucial question is whether it offers specific details that can be used to prevent an attack, like location, date or method.
In deflecting criticism of the handling of intelligence reports before Sept. 11, Ms. Rice emphasized that no specific information in any impending attack was discovered.
She also said: "I do not believe that we can have assurance that we're going to prevent another attack. We are doing what we can inside the country to disrupt them. We're doing what we can to harden the country. But the most important thing that we're doing, and it's what we need to stay focused on, is fighting this war to try to get them at their source."
Asked whether the administration had decided to disclose its concerns over another attack to deflect criticism over Sept. 11, Ms. Rice answered, "We don't play games with this."