BAGHDAD (AP) -- The military says U.S. soldiers in Iraq have found mass graves next to a torture center north of Baghdad.

The military says soldiers discovered blood-spattered walls and a metal bed frame attached to an electrical shock system inside the facility. The center sits in an area where al-Qaida insurgents are active and the military suspects al-Qaida had been running the facility.

It was found during an operation earlier this month. Twenty-six bodies have been found in the nearby graves.

Elsewhere, at least 13 Iraqis are dead following an attack today on a crowd gathered near U.S. soldiers. The soldiers had been handing out holiday gifts when the suicide bomber struck east of Baqouba.

At least 18 people have been hurt in the attack. It's not clear if there are any U.S. casualties among the dead or injured.