In addition to the sanctions regime and other diplomatic efforts to counter Iran, U.S. Ambassador James Jeffrey has announced that it will also contest “more actively Iran’s activities particularly in Iraq, Syria, and Yemen.” Isolating efforts against Iranian activity from Russian activity and others that work with it could prove difficult, however, and failures could escalate tensions with Russia. Israel’s high-stakes motivations to keep Iran out of Syria also complicate the picture, as their airstrikes against Iranian targets operating within striking distance of its borders have reportedly ceased since Russia delivered its high-tech S-300 air defense systems to the area. Jeffrey said that “in the past, Russia has been permissive in consultations with the Israelis about Israeli strikes against Iranian targets inside Syria…we certainly hope that that permissive approach will continue.” This working relationship, however, is not guaranteed, as any number of intentional or accidental events to damage or destroy it, potentially changing the dynamic calculus of the actors seeking and influential position in reaching an end to the conflict.
Source: US will push back at Iran activities in region, says US envoy to Syria