Al-Baghdadi became the leader of ISIS in 2010 and led it to a series of victories which captured a huge amount of territory, including the cities of Mosul in Iraq and Raqqa in Syria, though it has since suffered major defeats.
The Russian military said earlier this month that on May 29, its planes struck ISIL convoys attempting to leave Raqqa from the south and heading toward Palmyra, killing 80 militants. It provided no explanation for the delay in reporting the strike, which it said killed about 300 ISIS fighters.
Russia's military however said the U.S. was prepped about the place and time of the strike before it was carried out.
Russian Foreign Minister Sergei Lavrov later said that Russia still did not have 100 per cent certainty that al-Baghdadi was killed.
"We can not confirm", coalition spokesman Colonel John Dorrian said.
Russian Federation began bombing ISIS in Syria in September 2015, in support of Syrian President Bashar al-Assad. There was no mention of any specific leaders being killed in the report.
In March, U.S. Secretary of Rex Tillerson said that almost all of al-Baghdadi's subordinates have been killed.
The Islamic State leader last released an audio message on November 3 previous year, urging his followers to keep up the fight for Mosul as they defend the Iraqi city against a major offensive that began weeks earlier. Simultaneously, the US -led military coalition in Syria has supported the Syrian rebels who are fighting the Syrian government.
The report is the latest on the demise of Baghdadi.
There have previously been claims of Baghdadi being killed, but none were verified.
As a result, Iraqi officials are skeptical of Russia's claims, Reuters reported, and the us -led military coalition in the region could not confirm Baghdadi's death.
U.S. forces captured him in Falluja, Iraq, in 2004.
Rami Abdulrahman, director of the Syrian Observatory for Human Rights, cast doubt on the report Baghdadi may have been killed. Reuters also spoke to a colonel with the Iraqi national security service, who said that it is unlikely Baghdadi was there and that one of his aides may have been killed in his place. The group has since horrified the world with its atrocities in areas they held as well as attacks they claimed around the world that killed hundreds.
Abu Bakr al-Baghdadi, which is a nom de guerre, was born Ibrahim Awwad Ibrahim Ali al-Badri al Samarrai.
Baghdadi has made only one on-camera appearance since being named a "Specially Designated Global Terrorist" by the Department of State (information that leads toward his capture includes a $25 million reward), and is known for keeping a low profile.
Reports of al-Baghdadi's death "are being verified by various channels", it said, without elaborating.
So far, there has been minimal reaction from online supporters of IS to news of the reported death of the group's leader, it said.