U.S.-led coalition battling ISIS says there's no concrete evidence on whether ISIS leader Abu Bakr Al-Baghdadi is dead or alive.

The U.S.-led coalition battling Islamic State (ISIS) said on Friday it had no concrete evidence on whether the group's leader Abu Bakr Al-Baghdadi was dead or alive, Reuters reported.

At the same time, it also played down any significance he might have on the battlefields of Iraq and Syria.

"We certainly know that if he is still alive, we expect that he is not being able to influence what is currently happening in Raqqa or Mosul or overall in the ISIS as they continue to lose their physical caliphate," coalition spokesman U.S. Army Colonel Ryan Dillon told a Pentagon briefing.

"That said, we don't have any concrete evidence on whether or not he's dead either," he added.

Last week, the Russian Defense Ministry said that Al-Baghdadi might have been among a group of ISIS members who were killed in a Russian air strike on May 28 south of Raqqa, ISIS's de facto capital in Syria.

The Pentagon later said there was no evidence to prove that, but on Thursday Russia's Deputy Foreign Minister insisted that it is "highly likely" that Al-Baghdadi was killed in Russian airstrikes last month.

There have been many reports in recent years that Al-Baghdadi was injured or killed, but none of them have been confirmed.

Late last year, he refuted those reports by releasing an audio message in which he said he is "confident of victory" and called on the people of Mosul to fight the "enemies of God".