ANKARA, Turkey — In the first such incident since the U.S.-led coalition began airstrikes against Islamic State extremists last September in Syria, the Syrian government said Tuesday that its air defense system had shot down a U.S. surveillance drone near the northern city of Latakia.

U.S. officials in Washington confirmed that controllers had lost contact with an unarmed drone in northwestern Syria but said they did not know what had happened to it. “At this time, we have no information to corroborate press reports that the aircraft was shot down,” the Pentagon said in a statement attributed to a “defense official.”

Turkish military officials said the drone had been launched from the giant U.S. air base at Incirlik in southern Turkey and was one of four unarmed Predator drones based there.

The official Syrian news agency called the drone a “hostile U.S. surveillance plane,” and the major question about the incident is whether its controllers had sent it intentionally over northwest Syria, an area far from Islamic State strongholds in eastern Syria, or if it had strayed off course en route to or from Incirlik.