An undated mugshot of Abu Alaa al-Afarion released by the US State Department. [Photo/IC]

BAGHDAD - Iraq's Defence Ministry said on Wednesday the deputy commander of the Islamic State group had been killed in an air strike in the north of the country, but the US military denied coalition air forces had conducted such an attack.

The ministry said Abu Alaa al-Afarion was killed in a coalition attack on a mosque where he was meeting with other militants. However, the US Central Command strongly denied that a coalition air strike had hit the mosque.

It said it had no information to corroborate claims that the militant leader had been killed.

More than 60 countries led by the United States launched a campaign last summer to "degrade and destroy" the ultra-radical Sunni Islamist group, which seized large areas of Iraq and Syria. The coalition has been conducting air strikes against Islamic State in both countries.

"Based on accurate intelligence, an air strike by the coalition forces targeted the second in command of IS, Abu Alaa al-Badri," the Iraqi defence ministry said in a statement on its website.

Afar, whose real name is Abdul Rah man Mustafa Mohammed, is an ethnic Turkmen from the town of Tel Afar in northwestern Iraq, and is thought to be second in command of Islamic State under self-proclaimed caliph Abu Bark al-Baghdadi.

Baghdad was recently reported to have been incapacitated by an air strike in the same region of Iraq, and Afar was tipped to assume leadership of the organization. The Pentagon has denied those reports as well, saying Baghdad remains capable of directing operations and was not wounded in any raid.

On its website, the Iraqi defence ministry posted footage of what is said showed the air strike on the "Martyrs Mosque" in the village of al-Iyadhiya near Tel Afar, where Afar was a teacher and well-known preacher, according to a local official who requested anonymity.

There was no way to independently confirm the defence ministry statement. The Iraqi government has previously announced the death of Islamic State militants only for them to resurface alive.

Baghdad-based security analyst His ham al-Hashimi, who closely tracks Islamic State, said Atari's death was not yet proven, but confirmed the air strike had killed Abram al-Qurbash, also known as Mullah Meister, who recently took charge of Islamic State security in the northern province of Nineveh.