Islamic State group leader Abu Bakr al-Baghdadi is 'definitely alive', top Kurdish official claims

Islamic State group leader Abu Bakr al-Baghdadi is still alive, the top Kurdish counter-terrorism agent said on Monday, casting doubts on a "substantial" claim of the jihadi chief's alleged demise.

There have been numerous reports about Baghdadi's alleged death in recent months, including one this month by the Syrian Observatory for Human Rights this month.

Russia also claimed to have killed the IS head in June, but offered no proof to back their claim.

Lahur Talabany told Reuters that he was 99 percent sure that Baghdadi was alive and located south of the Syrian city of Raqqa.

"Baghdadi is definitely alive. He is not dead. We have information that he is alive. We believe 99 percent he is alive," Talabany said.

"Don't forget his roots go back to al-Qaeda days in Iraq. He was hiding from security services. He knows what he is doing."

Last week the Syrian Observatory for Human Rights said that it had information from top Islamic State group leaders confirming the death of the organisation's chief.

Days later, US defence chief Jim Mattis said the Pentagon was still not convinced Baghdadi was dead.

"If we knew, we would tell you - right now, I can't confirm or deny it," he said.

Talabany said IS was shifting tactics following the landmark defeat of the group in Mosul and it would take at least three or four years to eliminate the group.

With Raqqa's fall imminent, after defeat the group will wage an insurgency which would resemble al-Qaeda on "steroids", the Kurdish official said.

In 2014, following the rapid capture of Mosul and vast swathes of western Iraq by IS, Baghdadi declared himself the new leader of an "Islamic caliphate" from the Grand Mosque of al-Nuri in the Old City of Mosul.

The group and lone wolves inspired by it have claimed numerous terror attacks from the US to the Philippines, via Europe and the Middle East.