The US military can not confirm reports that the Islamic State group leader may have been struck in an airstrike, but a Pentagon official suggested Monday that lower-level figures may have been hit.

Speculation has swirled over the fate of jihadist leader Abu Bakr al-Baghdadi after local claims that he was killed or wounded in a strike by the US-led air armada targeting his group.

Baghdadi is the self-declared "caliph" of the radical group that has seized large swaths of territory in Iraq and Syria.

"Obviously there's a lot of conflicting reports out there on the fate of al-Baghdadi. But the bottom line from our perspective is we simply cannot confirm his current status," Pentagon spokesman Colonel Steven Warren said.

The Pentagon has said strikes on Friday hit a gathering of IS leaders in the northern Iraq city of Mosul, prompting rumors of Baghdadi's demise.

US officials are looking into the reports, but Warren suggested Monday that it was in fact lower "tactical-level leadership" who were hit.

"It was a 10-vehicle convoy which we had reason to believe may have consisted of ISIL battlefield commanders or battlefield leaders," Warren had said about the strike on Friday.

The death of Baghdadi would be a major victory for the US-led coalition, that in August launched a bombing campaign to roll back the large territorial gains of IS in Syria and Iraq.

US President Barack Obama said Sunday that the fight against IS would soon go on the offensive.

Last week, he unveiled plans to send an additional 1,500 American troops to Iraq to advise and train the country's forces.