US Air Strike Kills 6 Sunni Allies

US helicopters opened fire on two checkpoints manned by a pro-American group today, killing six members of the Sons of Iraq and injuring two civilians. The attack could exacerbate already strained tensions between the US and the Awakening Councils it employs, CNN reports. The US said that its helicopter opened fire after it spotted five people “conducting suspicious terrorist activity.”

US and Iraqi forces also promised a joint investigation of the incident. The Sons of Iraq and other Awakening Council groups like them are paid by the US to help with Iraqi security. The groups have recently been threatening to strike over late payments and neglect. Elsewhere, three US soldiers were killed by a roadside bomb, bringing the US death toll to 3,996. (More Iraq stories.)