Gunmen stormed a house in Youssifiyah, 12 miles south of the Iraqi capital at dawn, police said. Inside, the men all relatives from the Mashhada tribe were separated from women and children and then shot to death.

The motive of the attack could not be independently verified. But police, citing information from surviving relatives, said the victims had received threats from Sunni insurgents after participating in a reconciliation conference with Shias last month.

The conference was held in the neighbouring town of Mahmoudiyah in late February.

Also Saturday, the Iraqi Defence Ministry said Iraqi troops killed three suspected militants in Khan Bani Saad, a mixed town northeast of Baghdad. Two men were arrested in the raid, the ministry said in a statement. Seven others were captured in Balad Ruz, 45 miles northeast of Baghdad, it said.

A roadside bomb exploded near a police patrol Saturday morning in southeast Baghdad, wounding three policemen and one civilian, police said.

Earlier the bodies of 14 policemen were found Friday northeast of Baghdad after an al-Qaeda-affilated Sunni group said it abducted members of a government security force in retaliation for the rape of a Sunni woman by members of the Shia-dominated police.

The brutal killing occurred in one of the provinces surrounding Baghdad, where violence remains high despite a sharp drop in bombings and sectarian killings in the capital since the start of the US-led security crackdown last month.

Brig Gen Abdul-Karim Khalaf, an Interior Ministry spokesman, said the bodies were discovered Friday afternoon in Diyala province. The policemen were kidnapped Thursday on their way to their homes in Diyala for leave, he said.

On Friday, the Islamic State of Iraq said in a Web statement that it seized 18 Interior Ministry employees in Diyala in retaliation for "the crimes carried out ... against the Sunnis," including the alleged rape last month of a Sunni woman by policemen in Baghdad.