SAMARRA, Iraq (AFP) - Heavily-armed militants attacked the home of an anti-Qaeda militiaman north of Baghdad on Sunday, killing and decapitating his wife and two sons and killing another person in a brutal pre-dawn assault.

The militia leader, Mr Abu Salim, was not in the house at the time of the attack, which involved more than a dozen vehicles and fighters armed with heavy machine guns and other weapons and also left two of his young sons wounded.

Fighters attacked the militia leader's house in Jilam, a suburb of the predominantly Sunni city of Samarra, at around midnight on Saturday, and killed Mr Abu Salim's wife, two sons and another woman, a police colonel and another officer said.

They then decapitated his wife and two sons, and set off explosives around the house, injuring two other sons, aged four and five.

Policemen at a nearby checkpoint attempted to repel the assault, the officers said, but were unsuccessful and fled the scene when they ran out of ammunition and reinforcements that they had radioed for failed to arrive.

Mr Abu Salim is Jilam leader of the Sahwa, or Awakening, a collection of mostly-Sunni tribal militias that from late-2006 onwards sided with US forces against their co-religionists in Al-Qaeda, helping turn the tide of Iraq's insurgency.

But as a result, they are regarded by Sunni militants as traitors, and are regularly targeted in attacks.

Iraq is grappling with its worst prolonged period of violence since it emerged from a bloody sectarian war that left tens of thousands dead in 2006-07.

More than 240 people have been killed already this month, according to an AFP tally.

Analysts and diplomats have urged the Shiite-led government to reach out to the Sunni community, who allege they are mistreated by the government and security forces.

But with elections looming on April 30, political leaders have been loath to be seen to compromise.