CIA Director George Tenet (search) on Tuesday rejected charges that U.S. intelligence officials missed an opportunity to uncover a terror cell in Germany that was a key element in the Sept. 11, 2001, terror attacks.

German officials reportedly gave the first name and phone number of one of the hijackers who succeeded in destroying the World Trade Center more than two years before the attacks on America. But Tenet said his agency didn't get the last name of Marwan Al-Shehhi (search) until after the terror attack.

"You got a name, named Joe, and here's a phone number, Joe's phone number, no last name, and when we did some things to go find out some things, OK, we can give this all to you, OK. We never conclusively got where because we didn't have enough, but we didn't sit around, but I'd urge you to look at your classified page on this," Tenet testified before the Senate Intelligence Committee.

The federal commission reviewing the events of Sept. 11 is examining whether the United States failed to aggressively track this hijacker. The tip, received in March 1999, appears to be one of the earliest signs that U.S. officials had about one of the 2001 hijackers.

"The commission has been actively investigating the issue for some time," Philip Zelikow, executive director of the Sept. 11 commission, said Monday.

"I'm not going to comment on the progress of our investigation, but the Hamburg cell and what was known about the plotters" is an important part of the review, he said.

The New York Times, in its Tuesday editions, quoted German intelligence officials who said they asked U.S. officials to track Al-Shehhi. The Germans said they never heard back from U.S. officials until after Sept. 11.

Al-Shehhi was a member of the Al Qaeda cell in Hamburg, Germany, and a roommate of suspected Sept. 11 ringleader Mohammed Atta (search), who took over American Airlines Flight 11, which crashed into the north tower of the World Trade Center.

Al-Shehhi piloted United Airlines Flight 175 into the center's south tower in lower Manhattan.

A U.S. official told The Associated Press late Monday that thousands of full names of suspected terrorists come across the intelligence community's screens on a regular basis, making them hard to track.

"A first name — and a common one at that — is a scrap of information and doesn't take you anywhere without the benefit of hindsight," the U.S. official said, speaking on condition of anonymity.

The Sept. 11 panel, formally the National Commission on Terrorist Attacks Upon the United States (search), was established by Congress to study the nation's preparedness before the attacks and its response. It also is to recommend ways to guard against similar disasters.

In its previous hearings, the commission has highlighted intelligence miscommunications and missteps about Al Qaeda operatives dating back to the mid-1990s and hijackers who were allowed to enter the United States repeatedly despite lacking proper visa documentation.

The panel planned to meet Tuesday to discuss the status of its investigations, but the Hamburg tip was not on the agenda, Zelikow said.

The commission currently faces a May 27 deadline to finish its work, and has asked for at least a two-month extension, citing delays because of disputes with the administration over access to documents and witnesses.

Former New Jersey Gov. Thomas H. Kean (search), the commission's Republican chairman, has said the panel will be forced to pare down inquiries into intelligence failures if Congress doesn't act this week to give it more time.

Fox News' Peter Brownfeld and the Associated Press contributed to this report.