Iraq says strike may have killed top Islamic State commander

Iraq says a coalition air strike in the northwestern area of Tal Afar has targeted several of the Islamic State group's leaders, including a man presented as its second-in-command.

"Based on accurate intelligence, an air strike was carried out by the international coalition targeting the number two in the Daesh terrorist organisation Abu Alaa al-Afari," the ministry of defence said in a statement on Wednesday.

Daesh is an Arabic acronym for the Islamic State organisation, which took over swathes of Iraq last year.

It was not clear from the statement whether Afari was killed in the strike, which the ministry said targeted a gathering in the Martyrs' Mosque in Tal Afar's Al-Ayadiya district near the Syrian border.

The statement did not say when the raid was conducted but came with a video of the alleged hit - grainy black and white aerial footage of a building being destroyed in an apparently scarcely populated area.

The US-led coalition which has been pounding IS targets in Iraq and Syria did not immediately confirm the operation.

Afari's name emerged last month in reports claiming that IS head Abu Bakr al-Baghdadi was incapacitated in a coalition strike and handed over the helm of the organisation to Afari.

The Pentagon however said there was no reason to think Baghdadi had been wounded.

The structure of the organisation's senior leadership is secretive and IS has only released video or audio recordings of Baghdadi or the group's official spokesman Abu Mohammed al-Adnani.

The defence ministry statement also said the strike targeted the top IS judge in the group's self-proclaimed Jazira province, which includes Tal Afar, and "a large number" of the organisation's members.

The US state department last month put a $US7 million ($A8.8 million) bounty on information leading to Afari.