Russia defence ministry says one of its air strikes in Syria may have killed Abu Bakr Al-Baghdadi, leader of the world’s most brutal terrorist group, the Islamic State of Iraq and Syria (ISIS).

The ministry in a statement on Thursday however said it was still investigating the incident.

According to the statement, the airstrike carried out on May 28, targeted a meeting of the IS military council in the city of Raqqa, in northern Syria.

Quoting a statement published by the Russia-funded Sputnik news agency, BBC reported that more than 300 ISIS commanders and foot soldiers were said to be attending the meeting at the time of the strike.

“According to information that is checked through various channels, IS leader Ibrahim Abu-Bakr al-Baghdadi, who was killed as a result of the strike, was also present at the meeting,” the statement read in part.

But there have been a number of previous reports of Baghdadi’s death, though this is the first time that Russia has said it may have killed the IS leader.

Other media reports have previously claimed he had been killed or critically injured by US-led coalition air strikes.

John Dorrian, a Colonel and Spokesman for the US-led coalition, said the US could not confirm whether Baghdadi had been killed.

There has been no official comment from Syria’s government.

International Security expert are however doubtful that Al-Baghdadi would be at a meeting where there is a huge number of ISIS members.