BAGHDAD, Dec. 19 (UPI) -- The United States opened a so-called "friendly fire" investigation after 10 Iraqi soldiers were killed in a coalition airstrike targeting the Islamic State on Friday.
Defense Secretary Ash Carter said an American aircraft carried out the airstrike south of Fallujah, about 40 miles west of Baghdad. He said he expressed his condolences for the Iraqi deaths in a call with Prime Minister Haider al-Abadi. Carter said the incident was "a mistake that involved both sides," adding there would be an investigation.