Bush and Vice President Dick Cheney have also agreed to appear in a private meeting before all 10 members of the commission, instead of just the chairman and vice chairman.

"This commission has been charged with a crucial task. To prevent future attacks, we must understand the methods of our enemies. The terrorist threat being examined by the commission is still present, still urgent, and still demands our full attention," Bush said.

Because of the "exceptional nature" of the inquiry, "we have given commission members access to relevant presidential daily briefings, to my communications with foreign leaders, and to internal White House communications.

Bush added: "I've ordered this level of cooperation because I consider it necessary to gaining a complete picture of the months and years that preceded the murder of our fellow citizens on September 11, 2001."

The September 11 panel welcomed the surprise White House turnaround.

"We look forward to the commission's meeting with the president and the vice president and the public testimony of Dr Rice," said Commission chairman Thomas Kean, a Republican former governor of New Jersey.

Kean said the commission earlier got "some very good testimony" from Rice in a private session that he described as "candid," "factual" and "to the point."

"My hope is that she will replicate that testimony in public as well," Kean said, but also explore the differences "between the witnesses" -- a reference to testimony by former White House anti-terror czar Richard Clarke, who told the panel last week that Bush had not paid enough attention to the al-Qaeda threat.

The White House had previously said that Rice, 49, would not appear publicly before the independent bipartisan commission, citing separation of the executive and legislative branches of government.