The leaders of the 9/11 commission late Friday disputed a congressman's criticism that the panel did not adequately investigate a claim that four hijackers were identified as Al Qaeda (search) members more than a year before the attacks.

In a joint statement, former commission chairman Thomas Kean (search) and vice chairman Lee Hamilton (search) said a military official who made the claim had no documentation to back it up. And they said only 9/11 ringleader Mohamed Atta (search) was identified to them and not three additional hijackers as claimed by Rep. Curt Weldon, vice chairman of the House Armed Services and Homeland Security committees.

"He could not describe what information had led to this supposed Atta identification," the statement said of the military official.

They also said no else could place the other three hijackers with Atta in a purported terror cell code-named "Brooklyn" during the time period cited by Weldon.

The pre-Sept. 11 intelligence on Atta was disclosed recently by Weldon, who said a secret military unit called "Able Danger (search)" had identified the four hijackers as part of terrorist cell. He said the information should have been forwarded by the military to the FBI.

In response to the statement by Kean and Hamilton, Weldon accused the commission of purposely omitting information on Able Danger. He said in a statement that he will continue to push for a "full accounting of the historical record."

If proves correct, the intelligence would change the timeline for when government officials first learned of Atta's links to Al Qaeda. The Pentagon and at least two congressional committees are looking into the issue.

The other three hijackers mentioned by Weldon as being part of the terrorist cell were Khalid al-Mihdhar, Nawaf al-Hazmi and Marwan al-Shehhi.

Al Felzenberg, spokesman for the commission's follow-up project called the 9/11 Public Discourse Project, said this week the panel was unaware of intelligence specifically naming Atta. On Wednesday, he retracted the statement and confirmed the commission had been made aware of the intelligence.

During the July 12, 2004, meeting with the military official, the officer said he recalled seeing Atta's name and photo on an analyst's chart made by the secret Able Danger unit, the statement released by Kean and Hamilton said.

The relevant data discussed by the officer showed Atta to be a member of an Al Qaeda cell in New York City from February to April 2000, the statement said.

But the commission knew that according to travel and immigration records, Atta first obtained a U.S. visa on May 18, 2000, and first arrived in the United States on June 3, 2000, the statement said.

Kean, a former Republican New Jersey governor, and Hamilton, a former Democratic congressman from Indiana, said records had been sought from the U.S. Special Operations Command and none mentioned Atta or any other Sept. 11 hijackers. They were requested after staff members from the commission were told about Able Danger during a meeting in Afghanistan.

Weldon said Friday that Atta's name was specifically mentioned during the Afghanistan meeting, but Kean and Hamilton denied that Friday in the statement.