Russia starts drone surveillance missions in Syria

Russia has begun aerial surveillance missions over war-torn Syria, U.S. officials said, signaling the start of Moscow’smilitary operations in Syrian airspace.

The U.S. officials, who spoke to Reuters on condition of anonymity, could not say how many drone aircraft were involved in the surveillance missions. The Pentagon declined to comment.

The White House acknowledged that Moscow's intentions were unclear and that the prospect of deepening Russian military backing for Assad was troubling.

"We've made clear both in public and in private that doubling down on supporting Assad is a losing bet," said White House spokesman Josh Earnest.

One U.S. official, speaking on condition of anonymity, said the number of fixed-wing, piloted Russian aircraft stationed at the air base near Latakia, an Assad stronghold, had also grown dramatically in recent days.