NEW YORK, Feb 24: The Central Intelligence Agency (CIA) was given the first name and telephone number of one of the September 11 hijackers two-and-a-half years before the attacks on New York and Washington , but the United States appears to have failed to pursue the lead aggressively, American and German officials told the New York Times.

The newspaper said the German intelligence officials gave the CIA the first name and telephone number of Marwan al-Shehhi in 1999 and asked the Americans to track him. Al-Shehhi was determined to have piloted the United Airlines flight 175 into the south tower of the World Trade Center, the report said.

The information - the earliest known signal that the United States received about any of the hijackers - has now become an important element of an independent commission's investigation into the events of Sept 11, 2001, officials told the paper on Monday.

It is considered particularly significant because it may have represented a missed opportunity for American officials to penetrate the Al Qaeda terror cell in Germany that was at the heart of the plot. And it came roughly 16 months before the hijacker showed up at flight schools in the United States.

The attacks which destroyed the World Trade Center, damaged the Pentagon and crashed into a Pennsylvania field, claimed about 3,000 lives. The name and phone number in the United Arab Emirates were obtained by the Germans by monitoring the telephone of Mohamed Heidar Zammar, an alleged militant in Hamburg who was closely linked to the Al Qaeda plotters who masterminded the September 11 attacks, the Times said citing German officials.

But after the Germans passed the information on to the CIA, they did not hear from the Americans about the matter until after September 11, the report said, citing a senior German intelligence official.

The CIA decided that "Marwan" was probably an associate of Osama, but never tracked him down, the newspaper said citing American officials. The Germans considered the information on Shehhi particularly valuable, and the commission is looking into why it did not lead to greater scrutiny, the newspaper said.