At least 11 people have died in western Iraq after insurgents locked them into a house in Anbar province and blew it up, the US military has said.
A military spokesman, Major Jeff Pool, said it may have been a "vendetta attack" against people in the village, Karmah, for supporting the military.
Maj Pool said the owner of the house was a member of local security forces.
Sunni tribal leaders in Anbar province have recently persuaded many locals to join Iraq's security services.
The tribal sheikhs have been angered that fighters linked to al-Qaeda have been killing civilians. Anbar province has been a centre of the Sunni-led insurgency since the US-led invasion of Iraq in March 2003.
"According to eyewitnesses, two vehicles drove to a house in the village, locked the occupants inside and demolished the house with explosives," the spokesman said.
On Sunday, at least 23 Iraqi army recruits from Anbar were killed, and 27 wounded, in a suicide truck bomb attack on a recruiting centre east of Falluja.