Moussaoui repeated some assertions made previously, including that a 1990s plot by al-Qaida to shoot down Air Force One and assassinate President Bill Clinton was assisted by a top Saudi Embassy employee, along with claims there were direct dealings between senior Saudi officials and bin Laden.

The lawyers also said their case is boosted by sworn statements by 9/11 Commissioners John Lehman and Bob Kerrey, as well as Bob Graham, co-chairman of the Joint Congressional Inquiry into 9/11. Graham says he believes "there was a direct line" between some Sept 11 terrorists and the government of Saudi Arabia while Lehman, a former Navy secretary, explained close historical ties between the kingdom's government clerics and al-Qaida, the lawyers noted.

The court filing, coming less than two weeks after the death of Saudi King Abdullah, was made to meet a deadline set by Judge George B. Daniels.

In a website statement, the Saudi embassy noted the Sept 11 attack had been the "most intensely investigated crime in history and the findings show no involvement by the Saudi government or Saudi officials."

As for Moussaoui, the statement said: "His words have no credibility. His goal in making these statements only serves to get attention for himself and try to do what he could not do through acts of terrorism - to undermine Saudi-US relations."

Moussaoui was arrested on immigration charges in August 2001 after employees of a Minnesota flight school became alarmed he wanted to learn to fly a Boeing 747 with no pilot's license. He was in custody on Sept 11 and pleaded guilty in April 2005 to conspiring with the hijackers to kill Americans.

A psychologist testified for the defense at death penalty proceedings that Moussaoui had paranoid schizophrenia. Jurors spared his life.