Iraq's defense minister says he has launched an investigation into the killing of 10 Iraqi soldiers in an apparent American airstrike, adding that the wrongdoers would be "punished according to Iraqi law."

Speaking to reporters on Saturday, Khalid al-Obeidi said that an officer and nine soldiers were killed in a strike a day earlier near the Iraqi city of Fallujah, which is under Islamic State group control. He said he would "not neglect the blood of Iraqis."

U.S. Defense Secretary Ash Carter says the incident seems to be "a mistake that involved both sides."

The U.S. military did not release death toll figures. It says the strikes came in response to requests and information provided by security forces on the ground near Fallujah. The U.S. says it is currently investigating.