A bomb attack on Thursday morning in central Iraq at the home of two brothers, both policemen, killed all 10 of their family members, including women and children, police and medics said.

The 4:00 am (0100 GMT) attack in Mussayib, 60 kilometres (35 miles) south of Baghdad, struck the home of policemen Ahmed and Jihad Zuwaiyin as they and their families were sleeping, a police official in the Babil provincial capital Hilla and a doctor at Mussayib hospital said.

The victims of the attack included the two policemen and their wives, and six children, all aged around 10 or younger, the medic said. Both officials spoke on condition of anonymity.

It was unclear what type of bomb was used to carry out the attack, but the family's house was destroyed.

Mussayib, a predominantly Shiite town, lies in a confessionally mixed region dubbed the Triangle of Death because of the frequency of attacks during the worst of the insurgency that followed the US-led invasion of 2003.

Violence in Iraq is down from its peak in 2006 and 2007, but attacks remain common. More than 200 people have been killed in attacks since US forces completed their pullout from Iraq on December 18, according to an AFP tally.

Reflecting ongoing sectarian tensions amid a political row in Iraq, messages were posted on Monday on the Honein jihadist forum vowing further attacks against Iraqi Shiites.

"The violent attacks against the Rawafid (the name used for Shiites by Sunni extremists) will continue," Al-Qaeda front group the Islamic State of Iraq said in a statement, while claiming responsibility for attacks on Shiite pilgrims in the past month.

"The lions of the Islamic State of Iraq (will not cease their operations)... as long as the Safavid government continues its war. We will spill rivers of their blood as reciprocity."

The jihadists often invoke Iran's Safavid past, referring to the Shiite dynasty that ruled Persia between the 16th and 18th centuries, and conquered part of Iraq, when denouncing the Baghdad government, which they say is controlled by Tehran.