1.Russia, Turkey, and Iran signed an agreement to establish four de-escalation zones in western Syria on May 4, 2017 . The agreement intends to pre-empt the unilateral establishment of "interim zones of stability" by the US in Syria. The de-escalation zone agreement has provided Russia, Iran, and the Bashar al-Assad regime with a period of rest and regroup to refocus their efforts in Eastern Syria, particularly in areas where the US is leading operations with Syrian rebels.
2.Russia resumed its air campaign to focus on ISIS-held terrain in Eastern Syria from May 1 - 18. Russia, Iran, and the Assad regime likely intend to use the period of de-escalation to disrupt joint US-rebel operations to push north against ISIS in Homs and Deir ez Zour Provinces, while bolstering pro-regime advances against ISIS in both central Homs and eastern Aleppo. Pro-regime forces seized Jirrah Airbase from ISIS in eastern Aleppo Province on May 13 with Russian air support. Pro-regime forces also advanced towards a joint rebel-US base at Tanaf in eastern Homs Province amid the period of de-escalation. The US responded to the threat against Tanaf by striking pro-regime and Iranian-backed militia forces near the base on May 18, however.
3.Russia has also used the de-escalation agreement to reshape its deployment to Syria. Russia claimed to withdraw 30 aircraft from the Bassel al-Assad International Airport in Latakia Province upon signing the de-escalation agreement on May 4. The so called withdrawal does not represent the scaling down of Russian capabilities in Syria, nor does it preclude Russia from conducting airstrikes. Rather, Russia likely seeks to replace particular air assets with alternate air frames and capabilities better suited for the next phase of pro-regime operations in Syria, similar to previous Russian "withdrawals" throughout 2016. Russia reportedly deployed at least 21 M-30 Howitzers and a new shipment of missiles for the advanced S-400 Surface-to-Air Missile System operated by Russia in Syria in early May. Russia also deployed at least one A-50U 'Mainstay' Aerial Early Warning and Control Aircraft to Bassel al-Assad International Airport on the Syrian Coast as of May 3.
4.Russia deliberately drove fluctuations in the levels of violence in rebel-held Syria in order to compel local and international actors to submit to the Russian-Iranian-Turkish de-escalation zones. Russia escalated and subsequently tapered its air campaign in Syria prior to the Astana Talks in Kazakhstan from May 3 - 4, after which Russia, Turkey, and Iran signed the 'de-escalation zone' agreement. Prior to the agreement, Russia intensified its air campaign against mainstream elements of the Syrian opposition, relief providers, and civilian infrastructure such as hospitals in Idlib and Hama Provinces from April 26 - 30.
5.However, Russia subsequently halted its air campaign on the proposed de-escalation zones on May 1 and shifted its focus toward ISIS-held terrain in eastern Syria from May 1 - 18. The de-escalation zones provided Russia and its Iranian allies with a period of reset to recover following heavy losses in clashes with opposition forces in northern Hama Province throughout April 2017. Pro-regime forces have meanwhile begun to slowly escalate violence within the de-escalation zones, repeatedly violating the agreement with artillery strikes in Dera'a and Hama Provinces. Russia's continual use of violence to coerce local and international actors to accept agreements that primarily serve Russia, Iran, and Syrian President Bashar al Assad precludes any possibility of a legitimate, Russian-backed ceasefire agreement in Syria.(adapted from ISW)