Russia’s Defence Ministry on Friday said it is investigating whether one of its air strikes in Syria in May killed the leader of the Islamic State group Abu Bakr al-Baghdadi, reported Reuters. There were disputed reports on the matter as The New York Times reported the Russian Defence Ministry had claimed Baghdadi had been killed, but other agencies said the matter was still being investigated.

There have been a number of previous reports of Baghdadi’s death in the past. The Syrian government is also yet to make an official statement.

The Russian forces had carried out the air strike in May after receiving intelligence that a meeting of Islamic State group leaders was being planned, the ministry said in a statement on its Facebook page, reported Reuters. “On May 28, after drones were used to confirm the information on the place and time of the meeting of IS leaders, between 00:35 and 00:45, Russian air forces launched a strike on the command point where the leaders were located,” the statement said.

“According to the information which is now being checked via various channels, also present at the meeting was Islamic State leader Abu Bakr al-Baghdadi, who was eliminated as a result of the strike,” the ministry said.

The Russian report, however, could not be confirmed by the United States-led coalition fighting the Islamic State group.

The Islamic State group leaders had gathered at the command centre, situated in the southern suburb of Raqqa, the group’s de-facto capital, to discuss possible routes of retreat from the city, the statement said. The Russian military had initially sent drones to monitor the area and then dispatched a group of fighter jets to hit the Islamic State gathering, reported The New York Times. A number of senior leaders of the group are believed to have been killed in the strike. Around 30 field commanders and up to 300 of their personal guards were also killed, said the Russian defence ministry in the statement.

The Russian military said the United States was informed about the place and time of the strike in advance.

The last public footage of Baghdadi was released in 2014.