US Air Force backing ISIS opens warning fire on Russia's aircraft in Syria
This incident is an escalation, now involving live fire, of a similar, nearly identical incident on December 9th, 2017 (5 days ago) in which:
"An American F-22 fighter actively prevented the Russian pair of Su-25 attack aircraft from carrying out a combat mission to destroy the Daesh stronghold in the suburbs of the city of Mayadin in the airspace over the western bank of the Euphrates River on November 23. The F-22 aircraft fired off heat flares and released brake shields with permanent maneuvering, imitating an air battle,".
The Russian Federation appears to be continuing to build its case that it is the United States Air Force, or rogue elements within the US or external to it, are acting de-facto as the airforce for ISIS. Both the Mossad and the CIA, for example are known to have special-ops planes painted as US planes - false flags - in violation of Geneva Accords. A goal of a possible false flag operation, either from within the US or external to it, would be to increase tensions, even outright 'hot war' hostilities, between the two nuclear superpowers.
The Russian Federation is acting in Syria, legally, under international law - by invitation from the UN recognized and democratically elected, sovereign government in Syria. The US acts by virtue of its ability to act, contrary to international norms, in an attempt to reshape said norms.
The outcome of deconfliction talks were agreed to by Lavrov and Kerry, which gives the US a highly limited area of activity, in which they claim to be attacking ISIS. Russia has publicly been building a case that the US Air-force has been acting not as a force against ISIS, but rather are dropping supplies to ISIS and acting as its air cover. The last two incidents seem to confirm the Russian position.