The US said the Syrian jet had dropped bombs near Syrian Democratic Forces (SDF) fighters who are aligned with US forces in the fight against ISIS. Damascus said its plane had been on anti-Isis mission.
Russia's defence ministry said the US had given it no warning, following which Moscow was also suspending coordination over "deconfliction zones" that were created to prevent incidents involving US and Russian jets engaged in operations in Syria, reports the Guardian.
However, the Pentagon states that the Syrian jet had dropped bombs near US partner forces involved in the fight to extract Raqqa from Islamic State (ISIS) control.
Russia's deputy foreign minister, Sergei Ryabkov, said: "This strike has to be seen as a continuation of America's line to disregard the norms of international law.
"What is this if not an act of aggression? It is, if you like, help to those terrorists that the US is fighting against, declaring they are carrying out an anti-terrorism policy."
The development increases the risk of a possible air fight between US and Russian warplanes in Syrian skies.