Three US soldiers were killed when insurgents ambushed their convoy near the southern town of Diwaniya, the US Army said in a statement yesterday.

Clashes broke out after the convoy was attacked on Saturday night, in which witnesses said at least seven Iraqis were killed.

US forces have been fighting with Shi?ite militants in several parts of southern and central Iraq.

The US military said another soldier was killed on Saturday in al-Anbar province which stretches from Baghdad to Iraq?s western borders. It gave no further details.

Al-Anbar includes the town of Falluja where US forces have launched a crackdown on Sunni insurgents. The province has proved a hot spot for resistance to the US-led occupation.

At least 498 US soldiers have been killed in action since the US-led war in Iraq began 13 months ago.

At least two blasts echoed over central Baghdad yesterday and smoke rose from the Green Zonehousing Iraq?s US-led administration, witnesses said.

The Green Zone, a heavily fortified compound has been a frequent target for rocket and mortar attack by guerrillas fighting the US-led occupation.