Outgoing British leader Tony Blair, whose premiership has been dominated by his unpopular decision to join the 2003 invasion to topple Saddam Hussein, arrived in Iraq yesterday for his seventh and final visit as prime minister.

Blair, who was making an unannounced visit before he steps down from office in June, planned to reassure Iraqi Prime Minister Nouri al-Maliki that his departure will not bring an end to Britain's support.

Shortly after Blair arrived in the capital's Green Zone, three mortar rounds or rockets exploded in the heavily fortified compound, wounding one person, said US Embassy spokesman Lou Fintor said.

One round struck the British Embassy compound, according to security officials who spoke on condition of anonymity because they were not authorized to release the information. It was not known if Blair was in the embassy at the time.

Three US soldiers were killed Friday when their vehicle was bit by a bomb northeast of Baghdad, and two more in an ambush inside the city in which a gunmen opened fire on a patrol already hit by a roadside booby-trap.

Another soldier died in combat in western Iraq, one was shot dead while on foot patrol in Baghdad and the eighth was killed by a roadside bomb south of the capital that wounded two US and two Iraqi troops.

The deaths brought total US casualties since the March 2003 invasion to 3,412 and the total deaths in May to 69, keeping it on course to be one of the bloodiest months of the war for American forces so far.

Meanwhile, gunmen wearing Iraqi security force uniforms slaughtered at least 15 Kurdish villagers on Saturday, a local military commander said, blaming al-Qaeda for the massacre.

Brigadier General Nadhim Sharif, commander of Iraqi border forces in Diyala Province, told AFP the gang stormed the village of Qara Lus, near the Iranian border 100km east of Baghdad at dawn.

The mayor of the nearby town of Mandali, Abdul-Hussein Murad, confirmed Sharif's report that 15 men had been killed and added that a woman was also among the victims, bringing the death toll to 16.

Sharif said that the gunmen arrived at 6.00 am (0200 GMT) and went house to house, masquerading as security forces on a legitimate mission.

"They then searched the houses and ordered the people to leave. They separated men from the women and children and then they shot at the men, killing 13 immediately and two others a little later," he said.

The commander blamed the attack on the so-called "Islamic State of Iraq", an alliance of Sunni militant groups that serves as a front for al-Qaeda in Iraq and has a strong presence in the war-torn province of Diyala.

Qara Lus is a small community of Failis, or Kurdish Shias, a minority group that has been targeted in the past by Sunni extremists.