WASHINGTON -- The U.S.-led coalition fighting the Islamic State group launched an investigation Thursday into an airstrike against a terrorist target that could have killed civilians, the coalition announced in a statement.
The airstrike was conducted Thursday and destroyed a van that had Islamic State fighters inside firing a recoilless rifle, but coalition officials later determined the target was struck in the parking lot of a hospital where civilians might have been present, according to an Operation Inherent Resolve statement.
It was not clear how many civilians might have been killed.
The coalition "takes all allegations of civilian casualties seriously and this incident will be fully investigated and the findings released in a timely and transparent manner," the statement read.
When faced with allegations of killing civilians, coalition officials have said they typically launch an investigation to determine whether there is evidence of civilian deaths. If evidence is found, they open an official command investigation. There is no timeframe for how long such a probe might last.
Last month, the Pentagon said it had inadvertently killed 173 civilians in airstrikes targeting the Islamic State group in Iraq and Syria since it began the Operation Inherent Resolve bombing campaign in August 2014.
The airstrike on Thursday came as coalition warplanes were backing Iraqi security forces driving deeper into Mosul, Iraq's second largest city and the last urban center in the country held by the terrorist group. An Operation Inherent Resolve statement said the Iraqi security forces, after a brief tactical pause in Mosul operations, had begun advancing on three axis toward Mosul's center.
Iraqi security forces began the assault on Mosul in October, but they have faced a brutal urban battle and have cleared less than half the city of the terrorists who have held it for more than two years. The United States has backed the Iraqi forces with more than 7,650 bombs, rockets and mortars, but American and Iraqi officials have said the battle is likely to last well into 2017.