He spoke by telephone with Iraqi President Jalal Talabani and Kurdish regional President Massud Barzani as part of efforts to cement a "moderate bloc" behind the fragile government in Baghdad, said Bush spokesman Tony Snow.

Bush "discussed his commitment to a democratic and federal Iraq that can secure, sustain, govern itself, remains an ally in the war on terror," and sought their views on changing US strategy, said Snow.

"Both leaders spoke of how they share the President's vision for Iraq and were cooperating to be full partners against terrorism and tyranny, and building the new Iraq," he told reporters.

The US president later headed to the Pentagon for consultations with top US military planners, including some taking part from Iraq, ahead of unveiling a new strategy in a speech expected in early 2007.

Bush's conversations with Talabani and Barzani came after talks with powerful Shiite cleric and political leader Abdel Aziz al-Hakim and Iraq's top Sunni elected leader, Vice President Tareq al-Hashimi.

"We've talked in recent days about a moderate bloc that has Sunni, Shia, and Kurdish leaders, and both men fit into that moderate bloc and pledge their cooperation, not merely in building broader support for the government, but also taking action against those who want to destabilize it through acts of terror," said Snow.

Asked what would happen to key Iraqi figures who do not choose to join the "moderate bloc," as appeared to be the case with radical Shiite cleric Moqtada al-Sadr, Snow replied that Iraqis "do have to make choices."

"On the other hand, you've got Mr al Hakim, who represents the largest Shia bloc, Mr Hashemi, who certainly has the proxy of a lot of Sunnis, and you have the two most prominent of the Kurdish leaders all talking with the president," he said.

"They are agreed upon some real fundamentals. Number one is supporting the government, and number two is taking a tough line against those who want to destabilize the government by committing acts of terror," he said.

Snow did not include Iraqi Prime Minister Nuri al-Maliki, whom some in Washington accuse of not doing enough to quell violence by sectarian militias as his country threatens to descend into all-out civil war.

But he insisted that "the president is not doing the assembling. This has been going on within the Maliki government, trying to build this coalition. And the president is talking with willing partners."

A senior US official later disputed that Bush was taking the lead role in what he described as "an Iraqi process" of coalition building to support the government in Baghdad, stressing: "They're getting it together."

Separately, Snow denied a New York Times report that Saudi Arabia had warned that it would support Iraq's Sunni minority in sectarian strife against the Shiite majority if the United States withdraws its forces.

"That's not Saudi government policy," said the spokesman, who acknowledged that he had not discussed the matter with Riyadh's embassy in Washington or to officials in Saudi Arabia.

The Times, citing US and Arab diplomats, reported Tuesday that King Abdullah of Saudi Arabia delivered the warning to Vice President Dick Cheney in Riyadh two weeks ago.