Dozens of suspected al-Qaida militants showered a Shi'ite village with mortar rounds, then stormed the streets, killing at least 13 Iraqis, torching homes and forcing hundreds of families to flee, police said. Some villagers fought back, leaving three gunmen dead in the heart of one of Iraq's most violent regions. Even with nationwide violence ebbing to the lowest levels since January 2006, American commanders have warned that security is precarious in northern Iraqi regions such as Diyala - where the attack took place early Saturday - as al-Qaida and other militants have moved there to avoid coalition operations. The militant attack on Dwelah, about 75 kilometers north of Baghdad in Diyala, began about 6:30 a.m. with the mortar rounds, then 50 to 60 suspected al-Qaida fighters streamed in and opened fire, a police officer said. Among the 13 dead were three children and two women, the officer said, speaking on condition of anonymity because he was not authorized to release information about the raid. Villagers trying to fight back killed three gunmen, but the militants torched more than two dozen homes and around 500 families took shelter in neighboring towns, police said.