Updated

U.S. law enforcement never received information on Sept. 11 ringleader Mohamed Atta (search) and his possible connections to Al Qaeda, even though that information was known more than a year before the attacks that left approximately 3,000 people dead, Rep. Curt Weldon (search) said Tuesday.

Weldon, a Pennsylvania Republican and vice chairman of the House Armed Services and Homeland Security committees, said the hijackers were identified in 1999 by a classified military intelligence unit known as "Able Danger," which determined they could be members of an Al Qaeda cell. A military spokesman would not confirm or deny the unit's existence to FOX News.

A Weldon spokesman told FOX News that his boss stands by the claim that military intelligence identified the hijackers who were operating inside the United States.

In September 2000, the unit recommended that its information on the hijackers be given to the FBI "so they could bring that cell in and take out the terrorists," Weldon said in an interview with the Associated Press.

However, Weldon said Pentagon lawyers rejected the recommendation because they said Atta and the others were in the country legally.

"In fact, I'll tell you how stupid it was. They put stickies on the faces of Mohamed Atta on the chart that the military intelligence unit had completed and they said you can't talk to Atta because he's here on a green card," Weldon said.

He did not provide details on how the intelligence officials first identified the future hijackers and determined they might be part of a cell.

The congressman, who has occasionally been considered a maverick on Capitol Hill, initially made his allegations in a floor speech in June that attracted little attention. His talk came at the end of a legislative day during a period described under House rules as "special orders" — a time slot for lawmakers to get up and speak on issues of their choosing.

"Two weeks after 9/11, my friends from the Army's information dominance center, in cooperation with special ops, brought me a chart," Weldon said on the House floor. "What's interesting in this chart of Al Qaeda is the name of the leader of the New York cell. And that name is very familiar to the American people. That name is Mohamed Atta."

Weldon continued, saying that he brought the chart to Steve Hadley, who was then the deputy national security adviser. When Hadley said he wanted to show the chart to the president, Weldon asked if the CIA hadn't already done so. Hadley said no.

"So prior to 9/11, this military system that the CIA said we didn't need and couldn't do, actually identified Mohamed Atta and the cell in New York, and with Mohamed Atta they identified two of the other terrorists with him," Weldon said on the House floor. "Not only did our military identify Mr. Atta, our military made a recommendation on September 2000 to bring the FBI in and take out that cell."

Weldon told FOX that the "Able Danger" unit told its bosses that the information should be shared with the FBI.

A spokesman for U.S. Special Operations Command said there is no knowledge of Able Danger within Special Operations command headquarters right now.

Weldon said the unit is now defunct.

"It no longer exists," he told FOX. "It was disbanded."

Three other hijackers were also identified as Marwan al-Shehhi, Khalid al-Mihdar and Nawaf al-Hazmi. The information was not shared, in part, because those men were all in the United States on valid entry visas, Weldon's spokesman confirmed. Intelligence agencies at that time were uncomfortable singling out individuals who were in this country legally.

The issue resurfaced Monday in a story by the bimonthly Government Security News, which covers national security matters.

Pentagon spokesman Bryan Whitman said the Sept. 11 commission (search) looked into the matter during its investigation into government missteps leading to the attacks and chose not to include it in the final report.

Al Felzenberg, a spokesman for the Sept. 11 commission, confirmed that the panel's investigators had been aware of Able Danger but said they "don't recall any mention of Mohamed Atta, per se, or any mention of a ... cell."

The Sept. 11 commission report, considered the most exhaustive analysis of events leading up to the attacks, never mentions the defense intelligence group. If Weldon's claims are accurate, it means Atta was identified as a threat and it would amount to another missed opportunity.

One law enforcement source, however, told FOX News that he believes a repeat missed opportunity is unlikely because many of the information-sharing problems have been solved.

FOX News' Catherine Herridge, Nick Simeone and The Associated Press contributed to this report.