(CNN) -- The U.S.-led coalition will investigate after the Iraqi military said its forces suffered casualties from friendly fire during airstrikes on ISIS positions.
The coalition, which offered condolences for "the unfortunate loss of life" of Iraqis on the front lines, said the strikes took place Friday near Falluja.
U.S. Secretary of Defense Ash Carter called Iraqi Prime Minister Haider al-Abadi on Saturday to express his condolence, the Pentagon said. Both leaders reaffirmed their commitment to the U.S-Iraq partnership and to continued cooperation in the fight against ISIS, the statement said.
The Iraqi Joint Operations Command said one officer was killed and nine soldiers were wounded. Hakim al-Zamili, head of the Iraqi Parliament's security committee, said on Facebook that more than 20 soldiers were killed and 30 wounded.
The Iraqi military said one of its army regiments had moved on ISIS positions. Because of poor weather, the command said, the coalition was asked to step in. Two airstrikes inflicted heavy casualties on the enemy, allowing a rapid advance, but the third hit Iraqi troops, it said.
The coalition statement did not give a casualty estimate.
"Despite coordination with the Iraqi security forces on the ground, initial reports indicate the possibility one of the strikes resulted in the death of Iraqi soldiers," it said. "All of our airstrikes in Iraq are conducted with the approval of the government of Iraq in order to assist them in their fight against Daesh (ISIS); we take great measures to prevent these types of incidents while protecting our partnered forces."
Brett McGurk, the State Department special envoy to the anti-ISIS coalition, vowed a thorough investigation.
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