It seems that the temperature of Russian-American relations has risen to a critical level. First, the US military leadership announced its readiness to strike Syria not only in the army of Assad, but also in parts, which included Russian military advisers. And then US diplomats announced that if the UN does not dare to strike at Damascus (and all because Assad undertook to clean out the suburbs of his capital city – East Gutu from militants), then the Americans will do it themselves.
In general, the world hanging by a thread from bombing the capital of Syria with ships and aircraft of the United States. It was necessary to react, and Moscow reacted.