Russia's defence ministry has said it will treat US-led coalition planes and drones in Syria as targets, after the US military shot down a Syrian air force jet.
Moscow said it is halting communications with the US in order to prevent such incidents. It has also condemned the downing and called it a "flagrant violation of international law".
This comes after an American F/A-18E Super Hornet shot down a Syrian army jet on Sunday. The White House said the jet had dropped bombs near US-backed forces.
The defence ministry also called on the US military to provide a full account of why it decided to shoot down the Syrian SU-22 on Sunday.
Washington stated the US would "do what we can to protect our interests."
Spokesman Sean Spicer said: "The escalation of hostilities among the many factions that are operating in this region doesn’t help anybody.
"The Syrian regime and others in the regime need to understand that we will retain the right of self-defense, of coalition forces aligned against ISIS."
Russia, a key backer of Syrian president Bashar Assad, has been providing air cover to the government's offensive on the Islamic State group since 2015.