The disposition of forces in and around Syria

Institute for the Study of War:

Bashar al Assad Regime-Russia-Iran Coalition

Two Russian Su-24M ‘Fencer’ attack aircraft conducted several low-altitude passes in close proximity to the USS Donald Cook and the French frigate Aquitaine in the Eastern Mediterranean Sea on April 11. The Russian Navy conducted a firing drill off the Syrian coast in a likely attempt to deter U.S. and allied naval maneuvers near Syria on April 11.

Russia reportedly deployed four Tu-95MS ‘Bear’ and Tu-160M ‘Blackjack’ strategic bombers as well as an unspecified number of Il-78M tanker aircraft from the Engels Air Base in Southern Russia. Their final destination is unknown although they may be bound for Syria or the Hamedan Air Base in Western Iran. Russia previously targeted locations in Eastern Syria from the Engels Air Base.

Russian and regime forces enhanced the air defenses around Syria’s capital, Damascus, where the regime conducted its chemical weapons attack on April 7. Pro-regime forces deployed short- to medium-range surface-to-air missiles, including six Russian Pantsir-S2s, to the Mezzeh Military Air Base and other sites in Damascus. Pro-regime officials also reportedly issued an alert to the Syrian Arab Army to evacuate personnel and assets from military bases across Syria.

Regime and Russian aircraft relocated closer to heavily-defended commercial airfields across Syria. Aircraft relocated from the Seen (Sayqal), Dumayr, Shayrat, and the T-4 (Tiyas) Air Bases to the Bassel al Assad International Airport in Latakia Province, the Nayrab Air Base outside Aleppo City, and the Damascus International Airport.

Iranian proxies, including Lebanese Hezbollah, reportedly began exiting Syria. Hezbollah reportedly relocated a number of fighters from Syria into Lebanon. Hezbollah and other Iranian proxies reportedly also entered Iraq from positions along the Syria-Iraq border, including Abu Kamal in Eastern Syria.

Unspecified pro-regime elements reportedly evacuated a branch of the Syrian Scientific Studies and Research Center (SSRC) in Jamraya near Damascus. The SSRC is a Syrian government body responsible for research and development on advanced weapons systems, including ballistic missiles and chemical weapons.

Yemen

The Iranian-backed al Houthi movement escalated its series of ballistic missile strikes targeting Saudi Arabia. The strikes fit a pre-existing escalatory pattern but also coincide with Saudi Arabia’s expressed support for a military response in Syria. The al Houthi movement targeted Riyadh and two other locations in Saudi Arabia with a ballistic missile and kamikaze drones on April 11. It remains unclear if Iran directed the escalation against Saudi Arabia.
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There is more including the movement of US, British and French forces.  The inclusion of Yemen is interesting because it suggests that Iran will use its proxy forces in that country to attack the Saudis and other forces in the region.  Turkey which has recently been a player inside Syria appears to be sitting this one out at this point.