The Minneapolis FBI agent who asked the CIA to intervene in the case of suspected terrorist Zacarias Moussaoui is expected to meet Wednesday with top-level staffers of the House-Senate panels looking into pre-Sept. 11 intelligence failures.

Coleen Rowley will testify Thursday before the Senate Judiciary Committee as scheduled, but intelligence committee staffers wanted to hear from the agent who wrote a letter to FBI Director Robert Mueller outlining bureaucratic obstacles the field office was facing in conducting its investigation of Moussaoui.

Moussaoui, a French citizen of Arab descent, is now being held as the sole accomplice to the Sept. 11 hijackers.

Closed-door hearings into CIA and FBI intelligence lapses before Sept. 11 opened Tuesday with bipartisan promises that the congressional probe will focus on fact-finding, not finger-pointing.

"We're up and running with momentum," said Rep. Porter Goss, R-Fla., chairman of the House Intelligence Committee, who will run the first week of the intelligence hearings.

"We will be a fact-driven inquiry," Goss said as he stood next to Sen. Bob Graham, the Florida Democrat who will run the hearing on alternate weeks, under the rules the joint committee adopted during its first meeting Tuesday. "We will not be driven by outside pressures."

Already, the committee is faced with more information than it anticipated, which is both a plus and a minus for lawmakers looking to establish a new era in the intelligence agencies.

The good news, Goss said, "is we're getting great cooperation, great access. The bad news is there's lots more information to deal with than we thought when we started. But we'll get through that."

Hours before the committee convened for the first time in converted attic space in the Capitol, President Bush, in his most explicit criticism yet of FBI and CIA actions before the attacks, said: "I think it's clear that they weren't" communicating properly.

But, speaking at the National Security Agency, Bush also said there is no evidence that U.S. officials could have averted the attacks, even if agencies had worked together better.

The House-Senate committee will examine just that point and others as it seeks to uncover what clues might have pointed to the Sept. 11 airplane attacks on the United States, and how to prevent lapses in the future

"I think we're going to find that a lot of things were not done right by the CIA, the FBI, INS and perhaps other agencies," said Sen. Jon Kyl, R-Ariz. "Some of this is pretty serious" and "it will suggest ways we need to change."

"We need to be aggressive and rigorous in this inquiry, asking the right questions like who knew what? And if they didn't know it, why? And what did they do with the information they had?" said Sen. Barbara Mikulski, D-Md.

Investigators owe it to the victims and their families to be "serious, thorough and credible," said Mikulski. Open hearings will begin June 25.

The president made his comments when asked about an assertion by Egyptian President Hosni Mubarak that U.S. officials were warned about a week before Sept. 11 that Al Qaeda operatives were in the advanced stages leading toward an attack on an unspecified American target.

State Department spokesman Richard Boucher said, "This was credible but not specific information that pointed to Al Qaeda threats against U.S. interests, Egyptian interests and others as well."

Bush also said any additional inquiries into Sept. 11 — by other congressional panels or by an independent commission that some in Congress favor — could hinder efforts to prevent future terrorist strikes.

"What I am concerned about is tying up valuable assets and time and possibly jeopardizing sources of intelligence," the president said.

The investigation has been compared to the government's inquiry into how the United States missed preparations for Japan's surprise attack on Pearl Harbor. The last large-scale investigation of intelligence matters was a commission set up by Sen. Frank Church in 1975, which led to new congressional oversight of the CIA.

Rep. Nancy Pelosi of California, the ranking Democrat on the House Intelligence Committee, said one purpose of the hearings is to ensure federal law enforcement agencies don't react the wrong way to current criticism and spy more on Americans.

"I think we have to be smarter, more clever and protect the people in a way that also protects civil liberties and the Constitution," Pelosi said on television.

Government sources have disclosed in recent days that the CIA had important information in early 2000 about two of the future hijackers, Khalid Almihdhar and Nawaf Alhazmi, both of whom attended a mid-January 2000 meeting in Malaysia. A CIA official says two FBI officials were briefed on Almihdhar.

Neither agency gave the information enough significance to alert authorities to watch for Almihdhar or Alhazmi at U.S. borders until three weeks before the attacks.

Almihdhar, in fact, had been in and out of the United States several times. Both hijackers were aboard American Airlines Flight 77, which crashed into the Pentagon.

The Associated Press contributed to this report.