Russia said today it could not yet confirm that the elusive ISIS chief Abu Bakr al-Baghdadi had been killed in a targeted air strike by its military in strife-torn Syria last month. The liquidation of the leader of the Islamic State al- Baghdadi has not yet been confirmed, Russian Deputy Foreign Minister Gennady Gatilov said. "Not yet," the state-run TASS news agency quoted Russian diplomat as saying while responding to a question on the possible death of the ISIS leader, four days after the Russian Army announced that it may have killed Baghdadi on May 28 during an airstrike on the outskirts of the dreaded militant group's de facto capital Raqqa. US defense officials last week said they were unable to confirm the reports about Baghdadi's death. Col. Ryan Dillon, a spokesman for the US-led coalition's operation against ISIS in Syria and Iraq, said the coalition "cannot confirm these reports at this time." There have been a number of previous reports of Baghdadi's death or him being critically injured by US-led coalition air strikes. Abu Bakr al-Baghdadi, which is a nom de guerre, was born Ibrahim Awwad Ibrahim Ali al-Badri al Samarrai. Baghdadi has not been seen in public since proclaiming himself "caliph" in the Iraqi city of Mosul three years ago. Watch this also: In October 2011, the US officially designated Baghdadi as a "terrorist". It has offered a reward of up to $25 million for information leading to his capture or death. The ISIS terror group is known for imposing a hard-line form of Islam that has included stonings, amputations and beheadings. The ISIS seized Mosul, Iraq's second-biggest city, in June 2014 before claiming swathes of territory and launching deadly attacks on Western cities, including Paris and London.