Russia today warned it would track US-led coalition aircraft in Syria as potential "targets" and halted an incident-prevention hotline with Washington after US forces downed a Syrian jet.
The United States moved quickly to contain an escalation, with a top general saying Washington would work to relaunch the "deconfliction" hotline with Russia that was established in 2015.
The downing of the jet and Russia's response came as the US-led coalition and allied fighters battle to oust the Islamic State jihadist group from its Syrian bastion Raqa.
Analysts say neither Washington nor President Bashar al- Assad's regime appear to be seeking further confrontation, although the risks remain high in Syria's increasingly crowded battlefields and airspace.
Russia's foreign ministry accused Washington of failing to use the hotline before downing the plane near Raqa, and called for a "careful investigation by the US command" into the incident.
"Any flying objects, including planes and drones of the international coalition, discovered west of the Euphrates River will be tracked as aerial targets by Russia's air defences on and above ground," it warned.
"We will work diplomatically and militarily in the coming hours to re-establish deconfliction," said US General Joe Dunford, chairman of the Joint Chiefs of Staff, referring to the hotline.
Dunford noted that the hotline, which has been vital in protecting both US and Russian forces operating in Syria, remained in use "over the last few hours".
The Syrian jet was shot down yesterday evening after regime forces engaged the US-backed Syrian Democratic Forces (SDF), an alliance of Arab and Kurdish fighters battling IS, near Raqa.
An American F/A-18E Super Hornet shot down the Syrian SU-22 as it "dropped bombs near SDF fighters" south of the town of Tabqa, the coalition said in a statement.
Russia's defence minister said the pilot ejected "above IS-controlled territories" and that his fate is unknown.
Earlier yesterday, Syrian troops attacked the SDF near Tabqa, wounding several and chasing them out of town, the coalition said.
It said the warplane was shot down in line with the "rules of engagement".
But Damascus and regime ally Moscow condemned the "aggression".
The Syrian army said the plane was hit while "conducting a mission against the terrorist Islamic State group" and warned of "the grave consequences of this flagrant aggression".
Russia's deputy foreign minister Sergei Ryabkov said it was a "continuation of America's line to disregard the norms of international law".
"What is this if not an act of aggression?"
It was the latest skirmish between the coalition and regime forces in the increasingly tense and crowded space in Syria's north and east.
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