A suicide bomber killed nine policemen in near the western Iraqi city of Faluja, in Anbar province, on Monday, dpa reported.
News channel al-Arabiya reported that 13 other members of the Iraqi security forces were injured in the attack. The bomber drove a car loaded with explosives into the police checkpoint and detonated the charge.
Security duties in Anbar province were handed over to Iraqi forces by the US-led coalition in September, the first Sunni-majority province to do so, following a general fall in violence.
Meanwhile, an Iraqi police source confirmed on Monday that seven members of a family of the Yazidi faith have been killed by unidentified gunmen who attacked their home in the district of Sinjar, north-west of Mosul.
The incident took place late on Sunday night when the gunmen opened fire at the people inside the house, killing three women and four men," the Voices of Iraq (VOI) news agency reported.
Sinjar, 120 kilometres northwest of Mosul, has a large Yazidi population, a Kurdish faith with ancient Indo-European roots. Yazidis are primarily Kurdish speaking and live in northern Iraq.
According to the UN High Commissioner for Refugees (UNHCR), there are about 800,000 Yazidis all over the world. 550,000 of them live in Iraq.
Sunday's attack was not the first on Yazidis. In November, a Yazidi married couple were found strangled to death in Mosul.
The worst incident took place in April 2007 when twenty-three Yazidis were slain by gunmen, who apparently targeted them among passengers on a bus in northern Iraq.