U.S. officials say a Russian fighter jet came dangerously close to a U.S.-led coalition aircraft over Syria earlier this month.
One military official told the Reuters news agency that the Russian plane came close enough for its wake to be felt by the other pilot.
The officials said the incident, which occurred on October 17, did not appear to be threatening, but rather caused by the Russian pilot losing "situational awareness."
It wasn't immediately clear whether the non-Russian jet was a U.S. plane or one piloted by one of the U.S. allies helping the effort in Syria.
With scores of aircraft flying sorties over Syria, Russian and U.S. military operations there have communication procedures to reduce the risk of mishaps or midair collisions.
Still, the incident also follows more intentional close encounters between Russian and American planes. Last month, a Russian fighter jet came within 10 feet of an American spy plane over the Black Sea.