The aide to former Taliban Foreign Minister Wakil Ahmad Muttawakil made his claim in an interview aired Saturday with the BBC's former Kabul correspondent. The man, who wasn't identified, told Kate Clark he was sent to warn U.S. diplomats and the United Nations of the planned attacks just weeks before they took place.
But he said his warnings in July, 2001 to the U.S. consulate in Peshawar, Pakistan and the United Nations were brushed off.
Muttawakil, a reputed moderate, turned himself in to the authorities in Kandahar, Afghanistan this past February and was given over into U.S. custody.
The aide told Clark that Muttawakil learned of the impending attacks from Tohir Yuldash, the leader of an Uzbekistan Muslim movement. Yuldash, he said, was in Afghanistan at the time and had strong links to al Qaida.
The BBC quoted an unidentified American official as saying of the aide's warning that there were so many rumors at the time that a kind of "warning fatigue" had set in.
The aide had also been told not to mention Muttawakil's name, the network said, which meant that his warnings had been taken less seriously.
The network didn't give any further information on the aide's identity or whereabouts, or when the interview took place.