“According to information which we are checking through various channels, the leader of the Islamic State, Abu Bakr al-Baghdadi, was at the meeting and the strike destroyed him,” the statement said.
At a news conference, the Kremlin’s spokesman, Dmitry S. Peskov, declined to elaborate on the statement, referring questions about Mr. Baghdadi and the airstrike to the Defense Ministry.
Raqqa has been under attack in recent weeks: American-backed Kurdish and Arab forces, have been closing in on the ground, and an American-led coalition of Western and Arab air forces has attacked the city from above.
The Russian Defense Ministry said that it had“ warned the American side about the strike in advance,” according to the state-owned RIA news agency, but it was unclear whether Russia had shared intelligence on the meeting or cooperated in any other way with the Western-led coalition in Syria.
It was not clear whether the Russian military knew in advance that Mr. Baghdadi was at the gathering, or learned of this possibility only after the strike.
The Russian military does not draw a sharp separation between its psychological warfare operations and its media office, meaning the statement’s purpose could be tactical and intended to assist Russian forces in Syria. A claim that the terrorist leader has been killed, regardless of the evidence, sows doubt among Islamic State fighters.
Russia is believed to have an extensive intelligence operation targeting the Islamic State that makes use of the large numbers of Muslims from former Soviet states who have joined the group. A former Islamic State military commander, for example, was an ethnic Chechen from Georgia.
It is unclear whether this window into the Islamic State’s activities available to Russia but not the Western coalition aided in targeting the airstrike.
The Russian military said two models of Sukhoi fighter jets, Su-34s and Su-35s, had carried out the strike on what it described as “high level commanders of the terrorist group within the so-called military council of the Islamic State,” Interfax reported.
The strike also killed 30 field commanders and as many as 300 fighters, the military said. The strike lasted from 12:35 a.m. until 12:45 a.m., according to Interfax.
Ria reported that Russia learned of the meeting late in May, and while verifying the information ascertained that the commanders intended to discuss the retreat of their fighters from Raqqa.
The extent to which Mr. Baghdadi exerted day-to-day control over the Islamic State’s activities is not fully clear, but his death would be a major blow, easily the most prominent since Osama bin Laden, the leader of Al Qaeda, was killed in an American operation in Pakistan in 2011.
Mr. Baghdadi, who is believed to have been born in Iraq in 1971, grew up under Saddam Hussein’s regime. After the United States invaded the country and toppled Mr. Hussein in 2003, Mr. Baghdadi spent years imprisoned at Camp Bucca in southern Iraq.
He emerged from the jumble of Sunni extremist elements that battled the American forces and Iraq’s new Shiite-led government in the decade after the invasion. The Jordanian militant Abu Musab al-Zarqawi formed Al Qaeda in Iraq, but he eventually fell out with Al Qaeda because his wanton killings of Shiites were too brutal even by Qaeda standards.
An American airstrike killed Mr. Zarqawi in June 2006. Four months later, his successors declared the founding of the Islamic State of Iraq. It was one of several Sunni groups fighting mostly in northern Iraq.
The American military and Sunni tribesmen, banded together in what became known as the Awakening, left Al Qaeda, the Islamic State and other Sunni jihadists in disarray by 2010, but with an American troop withdrawal looming in 2011, tensions between Sunnis and the Shiite-dominated government of Prime Minister Nuri al-Maliki soared.
Mr. Baghdadi was named the head of the Islamic State in 2010, and his group seemed particularly adroit at turning these tensions to its advantage. After the Arab Spring uprisings of 2011, Syria became a fertile ground for jihadists like Mr. Baghdadi, who exploited the power vacuum left by the violent challenge to President Bashar al-Assad’s rule. The group also displayed a sophisticated command of social media to recruit potential jihadists from around the world, and to sow terror in the West.
Using porous borders between Syria and Iraq, the new jihadists overpowered Shiite-led authorities and rival Sunni factions in both countries, and established a stronghold in an overwhelmingly Sunni area. In the summer of 2014, the group declared itself a caliphate, a successor to early leaders of Islam.
Mr. Baghdadi has not been seen publicly in quite some time, even as the governments of Iran, Iraq, Russia and the United States have pounded Islamic State strongholds in major cities, and recaptured stretches of territory from the group.
Mr. Baghdadi last addressed his followers in a recording released in December 2015. His silence since then has led to persistent rumors that he has been wounded or killed. He was silent after one of his closest associates — Abu Muhammad al-Adnani, who headed the group’s efforts to export terror abroad, including overseeing attacks in Paris and Brussels — was killed in an airstrike in August.
Last November, the Islamic State released a blistering audio recording urging forces to remain firm in the face of the American-backed Iraqi offensive in Mosul.