Russia has completed a comprehensive air defense system in Syria that constrains the United States' ability to operate in the country and in the eastern Mediterranean, according to a new report published by the Washington-based Institute for the Study of War.The report paints a stark picture of increasing Russian entrenchment in Syria as Putin and the west have squared off in recent days over naval confrontations in Ukraine. The Russian moves include the deployment of S-300 and S-400 missiles and other weapons systems as well as electronic warfare capabilities in Syria. Underlying the Kremlin's efforts, the report claims, is a wider push to force American troops to withdraw from Syria. The Syrian deployments will also severely limit Israel's ability to launch strikes against Iranian forces in the country. Syrian media claimed that Israel targeted Iranian-backed militias in al-Kiswah south of the capital of Damascus, some 50 kilometers from the border with Israel, on Thursday evening."The US and Israel both must be prepared to suppress a larger number of air defense systems and use more expensive stealth aircraft such as the F-35 in Syria," the ISW's report said. However, the Russian strategy also has profound implications for US power projection throughout the region. "Russia stands to gain a long-term strategic advantage over NATO through its new capabilities in Syria," the report's authors write. "The US and NATO must now account for the risk of a dangerous escalation in the Middle East amidst any confrontation with Russia in Eastern Europe."Anna Ahronheim contributed to this report.