In a statement, Russian Defense Ministry spokesman, Maj Gen Igor Konashenkov said the Russian military "does not have reliable information" on the US raid.
The "increasing number of direct participants and countries that allegedly took part in this 'operation'", and "each one giving completely contradictory details, raises legitimate questions and doubts about its existence and especially the level of its success", he said, reported CNN.
In a statement announcing the killing of Al-Baghdadi, President Trump thanked Russia for its assistance, as well as Turkey, Syria, Iraq and the Syrian Kurds.
Russia, which supports embattled Syrian President Bashar Al-Assad and has also intervened militarily on his side, has a large base at Syria's Latakia and Konashenkov said that the Russian military had observed no strikes by US aircraft in the region.
"Firstly, on Saturday and in recent days, no air strikes were made on the Idlib de-escalation zone by US aircraft or the so-called 'international coalition' were recorded," Konashenkov said. "Secondly, we are not aware of any alleged assistance to the passage of American aviation into the airspace of the Idlib de-escalation zone during this operation."
The Russian military spokesman also said Al-Baghdadi's death "has absolutely no operational significance on the situation in Syria or on the actions of the remaining terrorists in Idlib".
( With inputs from IANS )