WASHINGTON -- An Army intelligence officer said yesterday that he told staff members from the Sept. 11 commission that a secret military unit had identified two of the three cells involved in the terrorist strikes of 2001 more than a year before the attacks.
Lieutenant Colonel Anthony Shaffer, who said he was associated with the ''Able Danger" unit, said that during a 2003 meeting in Afghanistan, he mentioned that the unit had identified Sept. 11 ringleader Mohamed Atta and three other hijackers as terrorist suspects.
The commission has denied that Atta's name or the name of any future hijackers were mentioned during the meeting.
Three months later, in January 2004, Shaffer said he was back in the United States and offered to follow up with the commission, but his offer was declined.
''I just walked away shocked that they would kind of change their mind, but I figured someone with equal or better knowledge . . . probably came and talked to them, so they must've taken care of it," Shaffer said.
Lieutenant Colonel Chris Conway, a Pentagon spokesman, said yesterday that an investigation into Able Danger is underway.
Al Felzenberg, spokesman for the commission's follow-up project, said the commission is awaiting the results of the Pentagon's investigation.
A statement issued Friday by former commission chairman Thomas Kean and vice chairman Lee Hamilton said the commission did not obtain enough information on the operation to consider it historically significant.
Shaffer said that Able Danger identified Atta and three other Sept. 11 hijackers in 2000 but that military lawyers stopped the unit from sharing the information with the FBI, out of concerns about the legality of gathering and sharing information on people inside the United States.
Shaffer said he and a Navy officer disagreed with that and tried to set up meetings with the FBI, but each time, the idea was rejected by lawyers from the special- operations command.
''There was a feeling . . . if we give this information to the FBI and something goes wrong, we're going to get blamed for whatever goes wrong," Shaffer said.