Shibu Crocker cites RIA News:
We have informed Russia that we do not support the statement of the Security Council. We are concerned that it can be perceived as a step that impedes efforts to achieve a political transition in Syria, and as a serious discrepancy with coalition actions from 60 countries, including all Syria’s neighbors to combat IS.
Moreover, the US State Department announced that the presence of the Russian military in Syria and the transfer of military equipment from Moscow to Damascus "complicates the situation." This was stated by John Kirby:
The whole situation in Syria is complex and, obviously, the presence of additional Russian armed forces there makes it even more complicated, there is no doubt about that.
Here Kirby did not explain, "makes it difficult" for whom? If for the United States, which with all its statements and steps confirms the support of an international terrorist, then of course ...