Russias Defense Ministry issued an ominous warning to Washington on Monday, saying it would track U.S.-led coalition aircraft operating in certain areas of Syria as potential targets.

Moscow also declared it would suspend the use of a military hotline meant to avoid conflicts between the U.S. and Russian military campaigns in Syria.

Any aircraft, including planes and drones of the international coalition, detected in the operation areas west of the Euphrates River by the Russian air forces will be followed by Russian ground-based air defense and air defense aircraft as air targets, Russias Defense Ministry said in the statement.

The Russians announcement is retaliation for the U.S. downing of a Syrian military plane on Sunday near the city of Raqqa. It was the first time an American fighter jet has shot down a Syrian aircraft in the civil war, with U.S. officials saying the action was taken to defend Washington-allied forces in the area.

Syria and its ally Russia condemned the incident, claiming the downed jet was targeting Islamic State militants.

Both the U.S. downing of the jet and Moscows response are evidence of escalating tensions between the two powers in Syria, as in recent months Washington has shown an increased willingness to target Syrian President Bashar Assads forces. Sundays incident came one month after a U.S. airstrike hit a pro-Assad militia that threatened U.S.-backed forces in southern Syria.