Gunmen in army uniforms swooped on a village south of Baghdad, stormed three houses and massacred 25 people from families linked to an anti-Qaeda militia before dawn yesterday, Iraqi officials said.

Among the dead were 20 men and five women, an interior ministry official said, while a security spokesman blamed al-Qaeda and said that 17 people had been arrested in connection with the murders.

The victims were found with either broken arms or legs, indicating they were tortured, according to a medical official at Al-Yarmuk hospital in west Baghdad with knowledge of police reports of the killings.

The brutal killings come as Iraq's political parties negotiate to form a government, nearly a month after parliamentary elections.

Security officials have warned that a protracted period of coalition building could give insurgents an opportunity to further destabilise Iraq.

"Men wearing uniforms and driving vehicles similar to those used by the army stormed three houses in the village of Sufia, in the region of Hour Rajab, and killed 25 people, including five women," said the interior ministry official, speaking on condition of anonymity.

A defence ministry official confirmed the details of the attack and the toll.

The interior ministry official said witnesses had told security forces the killers entered the village just before midnight Friday and had carried out the murders about two hours later.

They tied up their victims and shot them all either in the head or the chest in a rampage of violence, believed the worst against anti-Qaeda fighters since November 16 when 13 members of a tribe opposed to the Jihadis were murdered west of Baghdad.

"Our information is that the killers were from al-Qaeda," said Major General Qassim Atta, spokesman for the Iraqi security force's Baghdad operations, who put the death toll at 24 — 19 men and five women.