Russia said it is ending logistical military coordination with the United States and threatened to shoot down any aircraft west of the Euphrates River after the U.S. Navy shot down a Syrian regime jet.
The "deconfliction" communication agreement between Washington, D.C., and Moscow was previously established to avoid problematic encounters while aircraft operated above Syrian territory.
The U.S.-led international coalition fighting the Islamic State on Sunday said it shot down a Syrian regime fighter jet because it was attacking the U.S.-backed Syrian Democratic Forces militia near Tabqah. The SDF is leading the ground offensive in Syria to capture the Islamic State's stronghold of Raqqa.