Russia has provided evidence that Washington is collaborating with ISIS in attacks on Russian forces. http://russia-insider.com/en/politics/breaking-russia-presents-satellite-proof-us-troops-collaborating-isis-syria/ri21030
In one Washington-directed attack, ISIS tried to capture 29 Russian military policemen. However, Russian special forces entered the fray, and the result was spectacular losses for ISIS. http://russia-insider.com/en/military/us-secret-services-tried-nab-29-russian-troops-syria-and-got-their-butts-kicked-russian
In another attack Washington-directed attack, Russian General Valery Asapov and two Russian colonels were killed in an attack that violated agreements. http://www.moonofalabama.org/2017/09/syria-us-centcom-declares-war-on-russia.html#more
Sooner or later it will dawn on the Russian government that Washington is not a rational government with which diplomacy can be practiced, peace pursued, and agreements reached. Sooner or later it will dawn on the Russian government that far from being rational, Washington is a criminally insane collection of psychopaths in thrall to the military/security complex which, in turn, is in thrall to its massive profits.