ISIS leader Baghdadi may have been killed in strike: Russian military The Russian Defense Ministry said it's investigating.

 -- Russia's military said today that one of its airstrikes in Syria late last month may have killed the leader of ISIS.

The Russian Defense Ministry said in a statement it was "checking this through various channels" to determine whether ISIS leader Abu Bakr al-Baghdadi was killed in an airstrike May 28 targeting a command post where top ISIS officials were purportedly meeting in the outskirts of Raqqa, the terror group's de facto capital in Syria.

"According to information, which we are checking through various channels, at the meeting was also present the leader of ISIS who as a result of the strike was destroyed. The American side was informed about the time and place of the Russian aviation through the channels of cooperation," the ministry said in its statement.

The Russian Defense Ministry also posted on its official website a set of images said to show an aerial view of the ISIS command post just outside Raqqa May 13, and an aerial view May 29 showing the same site one day after the airstrike.

Russia's statement is far from definitive, and they were not corroborated by the United States.

"We can't confirm these reports at this time," said Col. Ryan Dillon, the spokesman for Combined Joint Task Force Operation Inherent Resolve, the U.S.-led coalition's operation against ISIS.

Hours after the defense ministry released its statement, Russian Foreign Minister Sergey Lavrov said in on-camera remarks that he does not have "100 percent confirmation" that Baghdadi has died.

There have been numerous reports of Baghdadi's demise or disappearance in the past that have turned out to be false.

ABC News contributor Steve Ganyard, a retired colonel in the United State Marine Corps and a former deputy assistant secretary of state, said there's no way to know whether the world's most wanted man was, in fact, killed.

"Raqqa is a city under siege, so the Russians have no hard evidence, there's no DNA evidence that would suggest that he's dead," Ganyard said in an interview today on "Good Morning America."

Ganyard noted that U.S. Department of Defense officials say there are no indications of any "chatter" within the ranks of the Sunni militant group that its elusive leader had been killed or wounded.

"There's nothing to back it up, no intelligence to back it up. So we need to remain very, very suspect of this claim," he said.

The U.S.-led coalition's military campaign is focused on ousting ISIS from its strongholds in Raqqa and in the Iraqi city of Mosul. But Ganyard said Baghdadi's death, if confirmed to be true, may not have a lasting impact on the fight.

"Probably in the short term, it'll have some effect in the fight around Raqqa. So the tactical situation, it may upset the ISIS leadership. But longer term, think about what happened after bin Laden, not much," Ganyard said, referring to Osama bin Laden, the founder and former leader of al-Qaeda who was killed in Pakistan in May 2011.

"This is an ideological struggle. It's not like North Korea where if Kim Jong-un was killed, the regime would collapse," Ganyard added. "Killing an individual of the state of ISIS may not have a long-term effect."