The country’s defence ministry said the change in position would apply to all aircraft, including those operating as part of the US-backed coalition.
It will also suspend a hotline between Russia and the US set up to prevent mid-air collisions.
The ministry said in a statement: “All kinds of airborne vehicles, including aircraft and UAVs of the international coalition detected to the west of the Euphrates River will be tracked by the Russian SAM systems as air targets.”
The warning followed after a US F-18 Super Hornet shot down a Syrian army SU-22 jet on Sunday in the countryside southwest of Raqqa.
Washington said the jet had dropped bombs near US-backed forces but Damascus said the plane was downed while flying a mission against ISIS militants.
Russia’s Defence Ministry said the suspension of its communication channel with the Americans would begin immediately.
The US did not use its communication channel with Russia ahead of the downing of the Syrian government warplane, the ministry was quoted as saying, accusing the US of a “deliberate failure to make good on its commitments” under the de-confliction deal.
“The shooting down of a Syrian Air Force jet in Syria’s airspace is a cynical violation of Syria’s sovereignty,” the ministry said.
“The US’ repeated combat operations under the guise of ‘combating terrorism’ against the legitimate armed forces of a UN member-country are a flagrant violation of international law and an actual military aggression against the Syrian Arab Republic.”
Russia, which has been providing air cover for Syria’s President, Bashar al-Assad, since 2015, has an agreement with the US aimed at preventing incidents involving either country’s warplanes engaged in operations in Syria.
Downing the jet was akin to “helping the terrorists that the US is fighting against”, Sergei Ryabkov, Russia’s Deputy Foreign Minister, said.
“In accordance with rules of engagement and in collective self-defence of Coalition partnered forces, it was immediately shot down by a US F/A-18E Super Hornet,” a statement released by US Central Command on Sunday said.
“The Coalition’s mission is to defeat ISIS in Iraq and Syria. The Coalition does not seek to fight Syrian regime, Russian, or pro-regime forces partnered with them, but will not hesitate to defend Coalition or partner forces from any threat.
“The Coalition presence in Syria addresses the imminent threat ISIS in Syria poses globally. The demonstrated hostile intent and actions of pro-regime forces toward Coalition and partner forces in Syria conducting legitimate counter-ISIS operations will not be tolerated.”