Al Felzenberg, who had been the commission's chief spokesman, said Tuesday the panel was unaware of intelligence specifically naming Atta. But he said subsequent information provided Wednesday confirmed that the commission had been aware of the intelligence.

It did not make it into the final report because the information was not consistent with what the commission knew about Atta's whereabouts before the attacks, Felzenberg said. The commission has gone out of existence, although a follow-up organization called the 9/11 Public Discourse Project continues to follow closely the Bush administration's progress in implementing their recommendations.

The intelligence about Atta recently was disclosed by Rep. Curt Weldon, vice chairman of the House Armed Services and Homeland Security committees. The Pennsylvania Republican is angry that the intelligence never was forwarded by the military establishment to the FBI.

According to Weldon, a classified military intelligence unit called ''Able Danger'' identified Atta and three other hijackers in 1999 as potential members of a terrorist cell in Brooklyn, N.Y. Weldon said Pentagon lawyers rejected the unit's recommendation that the information be turned over to the FBI in 2000.

According to Pentagon documents, the information was not shared because of concerns about pursuing information on ''U.S. persons,'' a legal term that includes U.S. citizens as well as foreigners legally admitted to the country.

Felzenberg said an unidentified person working with Weldon came forward Wednesday and described a meeting 10 days before the panel's report was issued last July. During it, a military official urged commission staffers to include a reference to the intelligence on Atta in the final report.

Felzenberg said checks were made and the details of the July 12, 2004, meeting were confirmed. Previous to that, Felzenberg said it was believed commission staffers knew about Able Danger from a meeting with military officials in Afghanistan during which no mention was made of Atta or the other three hijackers.

Staff members now are searching documents in the National Archives to look for notes from the meeting in Afghanistan and any other possible references to Atta and Able Danger, Felzenberg said.

He sought to minimize the significance of the new information.

''Even if it were valid, it would've joined the lists of dozens of other instances where information was not shared,'' Felzenberg said. ''There was a major problem with intelligence sharing.''

Weldon wrote a letter Wednesday to Thomas Kean, chairman of the 9/11 commission, and Lee Hamilton, the vice chairman, asking for information to be sought that would look at why the information was not passed on by Pentagon lawyers to the FBI.

The letter also asks the commissioners to find out why the panel's staff members did not pass the information about Able Danger onto commission members and provide full documentation.