The tape, which sounds like Baghdadi, lectures on a host of recent events, ranging from the North Korean conflict to IS' present state.

Baghdai was last seen in public July 2014, where he appeared to preach at the Great Mosque of al-Nuri in Mosul, after IS captured the city and a "caliphate" was proclaimed.

His absence since then was met with speculations.

However, according to US Spokesperson Ryan Dillon, Baghdadi is considered alive without proof of his death.

"Without verifiable evidence of his death, we have continued to assume that he is alive," Dillon said.

The 46-minute long speech was uploaded on the web.

This is the first IS speech since November, last year.

Baghdadi has a US $25m bounty on his head.