George Bush, the US president, has arrived at Al-Asad air base in western Iraq on an unannounced visit.

White House officials said he was accompanied on the trip on Monday by Condoleezza Rice, the secretary of state, and Stephen Hadley, the national security adviser.

Waiting for him at the base was Robert Gates, the defense secretary; General Peter Pace, the chairman of the Joint Chiefs of Staff; Admiral William Fallon, the commander of US forces in the Middle East; and General David Petraeus, the senior US commander in Iraq.

Geoff Morrell, a Pentagon spokesman, said: "This is the last big gathering of the president's military advisers and the Iraqi leadership before the president decides on the way forward."

Bush is on his way to Australia to attend the Asia Pacific Economic Conference summit.

His arrival coincides with a British military pullback from its base in the centre of the southern Iraqi city of Basra.

Petraeus report

Next week, Petraeus and Ryan Crocker, the US ambassador in Baghdad, are to testify before the US Congress.

Their assessment of the conflict, along with a progress report the White House must hand legislators by September 15, is expected to determine the next phase of US military involvement in Iraq.

Amid a rising US death toll, currently estimated at 3,700, and growing calls from the Democratic Party for a troop withdrawal, Bush is under pressure to decide whether to give Nuri al-Maliki, the Iraqi prime minister, more time to find a political solution to the crisis.

Critics of continued US military presence in Iraq say that the country's leaders are making almost no progress towards political reconciliation.

Bottom-up progress

Bush has described what he calls "bottom-up" progress in Iraq and often cites a drop in violence in Anbar province to justify a US presence in the country.

Al Jazeera's Rob Reynold's in Washington DC said Bush's decision to land in Anbar province can seen as a snub to al-Maliki's government in Baghdad.

He said Bush used the province to highlight Anbar as an example of how successful the "surge" strategy has been in the region, pointing to a drop in attacks by Sunni fighters.

The drop in violence is attributed to Sunni Arab leaders joining forces with the US military to combat al-Qaeda fighters, although it is unclear whether they will back a unified Iraqi government as well.

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