Suspected al Qaeda militants killed 10 Iraqi soldiers at a checkpoint in Iraq's restive Diyala province north of Baghdad on Monday, the US military said.
The military said 13 soldiers were also wounded in the attack. It gave no details of the incident, but an Iraqi army source, who spoke on condition of anonymity, said the victims were decapitated after being shot. The account could not be independently confirmed.
The army source said the attack took place in the town of Balad Ruz, where police arrested 75 suspected militants last week and seized a quantity of weapons.
Al Qaeda has proved a resilient foe in Diyala province, a religiously mixed region that is one of four northern provinces where US and Iraqi forces have sought to oust the Sunni Islamist militants from safe havens.
"Attacks of this nature against those who are working to protect the citizens of Iraq ... are yet another example of the barbarous nature of al Qaeda in Iraq," US military spokeswoman Major Peggy Kageleiry said.