George Bush called the two-day talks at Camp David to study the best way to help the new government of Nuri al-Maliki, the prime minister of Iraq. Maliki and his advisers will join the discussions by video conference for about an hour on the second day.

White House aides insist the talks will not result in an announcement on the withdrawal of US forces from Iraq. The two leaders are expected discuss what assistance the US can give Iraq. Al-Maliki has stated that his priorities are improving the electricity supply, reducing the threat of the militias and securing Baghdad.

The talks aim to capitalise on the killing Abu Musab al-Zarqawi, al-Qaeda's leader in Iraq, and the formation of al-Maliki's government of national unity.

On Friday, a senior Bush adviser, Dan Bartlett, said: "Everybody views the completion of a truly unity government as a moment of opportunity. Everybody also recognises that there's a window here in which it's important for them to show success."

On Sunday, the commander of US forces in Iraq and al-Maliki's national security adviser predicted that US troop levels, now  about 133,000, would fall over in the coming months.

US General George Casey suggested that the filling of crucial security posts in al-Maliki's cabinet last week and continued progress in training Iraqi forces would open the door to reducing US troop levels this year. Casey and other military commanders in Iraq will contribute to the talks by video conference.

Mowaffak al-Rubaie, the Iraqi national security adviser, told US television that the talks at Camp David would deal with US troop levels and predicted that US-led forces could be reduced by the end of 2006.

With congressional elections in November, opinion polls show the US public is unhappy about the situation in Iraq and Bush has the lowest approval ratings for a US president in a generation.