The Russian government said on Monday that any American aircraft flying west of the Euphrates River in Syria will be treated as legitimate targets in the wake of the U.S. shooting down a Syrian aircraft over the weekend.
"Any aircraft, including planes and drones belonging to the international coalition operating west of the Euphrates river, will be tracked by Russian anti-aircraft forces in the sky and on the ground and treated as targets," the Russian defense ministry said in an official statement Monday, as reported by the BBC.
American forces on Sunday shot down a Syrian Su-22 plane that was bombing U.S.-backed fighters in the province of Raqqa. Russia accused American forces of giving them no warning that they would shoot down the Syrian plane, and said that it would stop participating in the incident-prevention hotline that the two countries use to prevent midair collisions between American and Russian planes.
Russia had previously said it would suspend its participation in the incident-prevention hotline this past April after the U.S. launched 59 tomahawk missiles at a Syrian airbase in retaliation for the Syrian government's use of chemical weapons, although the BBC notes that the two countries continued communicating with one another to prevent collisions behind the scenes.