Representatives of the United States' Army had also reported about the death of the IS group's leader, but later the report was either denied or al-Baghdadi released video messages with calls for his supporters.
However, asked later about that claim at a news conference in Moscow, Russian Minister of Foreign Affairs Sergey Lavrov said: "I don't have a 100 percent confirmation of the information". It provided no explanation for the delay in reporting the strike, which it said killed about 300 ISIS fighters.
Regardless of al-Baghdadi's personal status, Dillon said that the Islamic State group is "a losing organization" that would soon lose its control of its last two major urban strongholds _ the Iraqi city of Mosul and the Syrian city of Raqqa.
But while al-Baghdadi is an iconic figure for Islamic State - the leader who announced its caliphate spanning parts of Iraq and Syria - it would be able to cope with his loss, according to Sami Nader, head of the Beirut-based Levant Institute for Strategic Affairs.
Al-Baghdadi was born in Iraq in the early 1970s.
The ISIS-run Aamaq news agency did not confirm the death of the militant leader.
They said the strike came as the militants gathered to discuss the group's withdrawal from Raqqa.
The Americans are investigating whether the strikes were in the precise area the Russians are claiming and whether there is any intelligence on who may have been in that location, the US official said.
Since a now infamous 2014 video recording where he declared the establishment of an ISIS "caliphate" from a mosque in Mosul, al-Baghdadi has kept a decidedly low profile aside. It's not the first time al-Baghdadi has been reported killed (here and here).
In response to Russia's claim that its strike killed an ISIS emir named Ibrahim al-Nayif al-Hajj, the human rights group says, "this news is not true", adding that it believes Hajj was killed in an attack on May 24 at al-Baroudeh village.
The IS 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.
There has been no statement from Islamic State or other jihadist groups regarding al-Baghdadi's status.
Islamic State and al-Qaeda differ in terms of how important the leadership is to the group, so the death of al-Baghdadi wouldn't have the same impact as Osama bin Laden's did, she said.
He was killed in an August 2015 air strike by the U.S. in Iraq.
In Iraq, the US-backed government has been battling to recapture Mosul since October previous year after driving the group out of most of the rest of the territory it had seized. The U.S.is offering a $25 million reward for information leading to his death or capture.