ISIS faces mounting pressure upon its stronghold of Ar-Raqqa City and its access to the Syrian-Turkish Border via Aleppo Province. The Syrian Democratic Forces successfully isolated Manbij in Eastern Aleppo Province in an operation that began on May 31. Meanwhile, Pro-regime forces advanced into Ar-Raqqa Province on June 2. These overlapping pressures forced ISIS to abandon an ongoing offensive against key opposition strongholds in Northern Aleppo Province.
The tempo of Russian air operations has dramatically escalated in Syria. The rate and breadth of Russian airstrikes nearly tripled from May 29 – June 2 in comparison to the previous five day period. ISW was able to assess a total of 29 Russian airstrikes with low and high confidence beginning on May 29 and only 10 locations from May 24 -28.
The Islamic State of Iraq and al-Sham (ISIS) has mounted a major offensive against opposition groups in Northern Aleppo Province, threatening the total collapse of the last pocket of opposition-held terrain along the Syrian-Turkish Border. The looming defeat of the opposition on the Mare'a Line poses a significant risk to the long-term success of the anti-ISIS campaign by foreclosing future partnership with Sunni Arabs in Northern Syria and deepening U.S. overreliance on the Syrian Kurdish YPG
ISIS conducted an unprecedented series of complex suicide attacks in regime-held Tartus City and Jableh on the Syrian Coast on 23 MAY, killing at least 150 civilians and wounding over 200 others. ISIS will likely escalate its attacks against Alawites on the Syrian Coast during the upcoming holy month of Ramadan. Meanwhile, ISIS seized at least six villages in Northern Aleppo Province in a major setback for efforts by the U.S. and Turkey to deny ISIS access to the Syrian-Turkish Border.
Russia is waging a multi-front campaign against Turkey in order to weaken NATO in line with its strategic objectives. The use of a high-end Soviet-era MANPADS against a Turkish helicopter in southeastern Turkey on May 13 could indicate that Russia is providing meaningful military support to the Kurdistan Workers' Party (PKK) insurgency. The incident, if indeed an escalation by Russia, is yet another infringement of a sovereign NATO partner.
The International Syria Support Group (ISSG) agreed to new measures to reinforce a nationwide 'cessation of hostilities' following a meeting on May 17. The ISSG pledged support to a campaign of "air bridges" starting on June 1 if actors continue to deny humanitarian access to besieged regions. The ISSG also threatened to exclude parties with a "persistent pattern of noncompliance" from the ceasefire. The meeting nonetheless failed to set a clear date for the resumption of the Geneva III Talks.
A temporary ceasefire ended in Aleppo City on May 11, sparking a new wave of violence throughout the city and its outskirts. The U.S. and Russia brokered the local truce on May 5 as part of an effort to reinstate a nationwide 'cessation of hostilities'. Meanwhile, Lebanese Hezbollah military chief Mustafa Badreddine reportedly died in an unidentified explosion near Damascus less than a week after the Islamic Revolutionary Guard Corps suffered one of its largest single-day combat losses in Syria.
The U.S. and Russia brokered an agreement to extend a temporary "regime of silence" to Aleppo City for 48 hours beginning on May 5. The agreement follows 10 days of violence in Aleppo City that killed at least 250 people and damaged at least 5 hospitals. Nonetheless, the renewed diplomatic effort to prevent an escalation in Aleppo City and re-institute a nationwide 'cessation of hostilities' faces severe challenges.