(CNN) -- At least 76 men were killed Wednesday when the Iraqi air force struck a building in Mosul believed to be used by Islamic militants as a temporary detention center, an Iraqi official told CNN.
The location is in the western part of Mosul, a city in northern Iraq.
The building was thought to be used by the Islamic State, formerly known as the Islamic State in Iraq and Syria (ISIS), according to Mohammed Fadhil, the director general of the Nineveh province health directorate.
Other local officials from the Mosul civil defense ministry said dozens of those killed were civilians and that the building housed people who opposed the Islamic State or violated Islamic Sharia law.
CNN was not able to get a comment from the Iraqi military regarding this claim but Iraqi state television reported the airstrike on the building killed "ISIS militants."
The Islamic State -- known for killing dozens of people at a time and carrying out public executions, crucifixions and other acts -- has taken over large swaths of northern and western Iraq as it seeks to create an Islamic state that stretches from Syria into Iraq.