Former Vice President Al Gore testified behind closed doors yesterday before the independent commission investigating the September 11th attacks on the United States.
"The former Vice President was candid and forthcoming during the three-hour meeting," the panel said in a statement. "We thank him for his continued cooperation with the commission."
Mr Gore's appearance came a day after that of his ex-boss and fellow Democrat, Mr Bill Clinton, who also testified in a "closed private session." Mr Clinton's testimony lasted four hours.
On Thursday, Ms Condoleezza Rice, President Bush's national security advisor, testified at an open hearing. She said a terrorist threat had gathered for more than 20 years "and America's response across several administrations of both parties was insufficient."
"Tragically, for all the language of war spoken before September 11th, this country simply was not on war footing," she said.
Mr Bush and Vice President Dick Cheney are expected to testify together at a private session with the commission. The date of that meeting has not been announced.
Mr Gore was the Democratic nominee for president in 2000, losing to then-Texas Governor Bush after a controversial, 36-day recount in Florida, which ended when the US Supreme Court intervened 5-4 to stop the recount.