The airstrike was conducted around the city of Homs, said the official, who asked not to be identified because he was not authorized to discuss the matter publicly.
The United States was given one hour’s notice before the strike took place, the official said. The notice was sent in Baghdad, where the Russians have set up a coordination unit with Iraq’s government. A high-ranking Russian officer there notified a U.S. military official at the U.S. Embassy in Baghdad, the U.S. official said.
It was not clear whether the target of the Russian airstrike was the Islamic State militant group or more moderate Syrian rebels combating the forces of Syrian President Bashar Assad, the official said. The U.S. had not yet assessed the damages from the airstrike.
It was also not immediately apparent whether the attack signified the start of regular Russian airstrikes.
The development comes one day after the Pentagon announced it would begin talks with Russia about “de-conflicting” operations in Syria, where a U.S.-led coalition is conducting daily airstrikes on Islamic State targets.
Both the U.S.and Russia view the Islamic State as a common enemy, but Russia supports Assad’s regime as the most effective force battling the militant group, while the US. wants Assad to step aside because of atrocities it says he has committed against civilians to retain power during Syria’s 4-year-old civil war. The U.S. is backing Syrian rebel groups that so far have proven ineffective against the Islamic State and Assad’s forces.
The purpose of these de-confliction discussions will be to ensure that ongoing coalition air operations are not interrupted by any future Russian military activity, to ensure the safety of coalition air crews and to avoid misjudgment and miscalculation,” Pentagon press secretary Peter Cook said Tuesday.
News of the Russian airstrike came after Russia’s parliament granted President Vladimir Putin permission to launch airstrikes against the Islamic State in Syria.