A new Pentagon report knocks down the idea that a secret military unit had garnered intelligence a year before the Sept. 11 attacks that might have stopped the hijackers, a senior defense official said Thursday.

Lawmakers were supposed to be briefed Thursday on the Defense Department inspector general's report, and officials hoped to post a redacted version of the report on the Pentagon's Web site as early as Thursday afternoon, two officials said. The officials, who spoke on condition of anonymity because the report had not yet been released, declined to provide further details about the study's conclusions.

The report was ordered following the assertion that four of the 19 hijackers were identified in 2000 by a classified military intelligence unit known as "Able Danger."

The claim was made by a former intelligence officer who worked on Able Danger, Lt. Col. Anthony Shaffer, and by Rep. Curt Weldon, a Pennsylvania Republican and vice chairman of the House Armed Services and Homeland Security committees.

Weldon said the unit used data mining to link ringleader Mohamed Atta and three other hijackers to Al Qaeda more than a year before the Sept. 11, 2001, terrorist attacks.

Weldon said the intelligence unit wanted the information given to the FBI, but that Pentagon lawyers rejected the recommendation.

The Pentagon has previously acknowledged that some employees recall seeing an intelligence chart identifying Atta as a terrorist before the attacks.

John Tomaszewski, Weldon's press secretary, said they have been told the report's release was imminent.