The family were poor refugees who had fled violence in Baquba, Diyala's provincial capital, Raheem said.

Diyala is one of the most dangerous areas of Iraq, with frequent violence reported between ethnic Arabs, Kurds and Turkmen.

Fighters from al-Qaeda, a Sunni group, and members of Shia militia organisations have often battled each other in Diyala after being forced out of other parts of Iraq.

Shia fighters hold the most control over the province, security sources say.