BAGHDAD — An “Islamic State” leader has been killed in an air strike in the northern Iraqi city of Mosul, residents and a local medical source said on Thursday.

Radwan Taleb al-Hamdouni, whom the sources described as the extremist group’s leader in Mosul, was killed with his driver when their car was hit in a western district of the city on Wednesday afternoon.

The ultra-hardline IS swept through northern Iraq in June almost unopposed by the Iraqi army, consolidating gains made in the country’s Sunni heartland region of Anbar.

Hamdouni was buried later on Wednesday. Large numbers of supporters, some carrying black “Islamic State” flags, attended the funeral, one source said.

Two U.S. officials said they were unable to confirm whether Hamdouni had been killed.

Hamdouni had been the IS “wali”, or governor, of Mosul, which was captured by the group in June and is the largest city in a self-declared “Islamic State” caliphate straddling the border between northern Iraq and eastern Syria.

IS leader Abu Bakr al-Baghdadi chose a mosque in Mosul to deliver a sermon in July, his only appearance since he assumed the title of caliph, or Muslim leader.

Sources in Iraq said two weeks ago that he had been wounded in an air strike. The movement later released a defiant audio statement by Baghdadi.