The US military says it killed around 70 militants in a series of air strikes in and near Iraq’s western city of Ramadi on Sunday.It said at least 20 militants were killed when an F-15 aircraft bombed a group of men burying a roadside bomb. Local witnesses say those killed were innocent civilians who had gathered to look at the wreckage of a US vehicle destroyed the day before, in an attack that killed five American soldiers. A local hospital reported 25 civilian deaths.Ramadi lies in al-Anbar province, one of the majority Sunni areas where opposition to the draft constitution runs strongest. The rules of Saturday’s referendum on the text say two-thirds must vote “No” in at least three provinces to stop it coming into effect. Most Shi’ite and Kurdish-dominated provinces are reportedly running heavily in favour, with al-Anbar and one other region massively against.