The U.S. military says it has no idea if ISIS leader Abu Bakr al-Baghdadi is alive or dead, despite a claim by Russia that it killed the terrorist leader along with 300 other ISIS fighters in an airstrike near Raqqa last month.

"We do not have any definitive proof to corroborate their claims," Col. Ryan Dillon, the chief U.S. military spokesman in Iraq told reporters at the Pentagon Friday.

Dillion said the U.S. has no "concrete evidence" either way about the status of Baghdadi. He said if Baghdadi is still alive, he is in no position to influence events in Mosul, where the last remnants of ISIS are about to be defeated by Iraqi forces.

Pentagon officials were skeptical last week about Russia's claim about Baghdadi, and its claim that 300 other fighters were killed.

"We have seen no evidence that is true," a Pentagon official told the Washington Examiner.