ISIS Collapses Opposition Frontline in Northern Aleppo Province

The Islamic State of Iraq and al-Sham (ISIS) has mounted a major offensive against opposition groups in Northern Aleppo Province over the past week, threatening the total collapse of the last pocket of opposition-held terrain along the Syrian-Turkish Border. ISIS seized at least six villages in Northern Aleppo Province on May 27, besieging the critical opposition stronghold of Mare’a and entering the outskirts of the border town of Azaz. ISIS later entered the town of Mare’a on May 28 under the cover of up to nine Suicide Vehicle-Borne Improved Explosive Device (SVBIED) detonations before withdrawing in the face of heavy resistance from the opposition. Opposition groups successfully recaptured several villages near Azaz in a counterattack on May 28 - 30, but the situation remains tenuous. ISIS has launched near-continuous attacks against Mare’a over the past week, while the Syrian Kurdish YPG assumed control over the adjacent town of Sheikh Issa on May 30 in exchange for the safe passage of more than 6,000 civilians from the town. Meanwhile, the UN Office for the Coordination of Humanitarian Affairs (OCHA) warned that the fighting has displaced thousands of civilians in Northern Aleppo Province where over 160,000 civilians already live in temporary residences, informal settlements, or humanitarian camps.

These gains by ISIS mark the latest in a series of recent setbacks for the opposition in Northern Aleppo Province. On April 7, the Hawar Kilis Operations Room – a coalition of opposition groups backed by the U.S. and Turkey that includes fighters vetted by the U.S. Department of Defense - captured the ISIS-held town of Al-Rai in Northern Aleppo Province with the aid of cross-border artillery fire and coalition airstrikes. The operation was part of a wider offensive to clear ISIS from the Syrian-Turkish Border. The rapid advance along the border nonetheless left opposition forces vulnerable to an attack on their exposed southern flank. ISIS launched a two-pronged counteroffensive on April 10 - 11, seizing several villages near Azaz and recapturing the town of Al-Rai – a key route for illegal smuggling of foreign fighters and supplies. On April 14, ISIS mounted another attack that temporarily entrapped opposition groups against the Syrian-Turkish Border after entering four towns including Hawar Kilis – the namesake of the Hawar Kilis Operations Room. The opposition continued to suffer a steady erosion in terrain over subsequent weeks despite continued coalition support and several effective local counterattacks against ISIS.

The looming defeat of opposition groups in Northern Aleppo Province poses a significant risk to the long-term success of the anti-ISIS campaign. The U.S. and Turkey have provided varying levels of support to opposition factions along the so-called ‘Mare’a Line’ as part of a wider effort to isolate the ISIS stronghold of Ar-Raqqa City from the Syrian-Turkish Border. Turkey has repeatedly called for the U.S. to increase its support for Sunni Arab opposition groups in Northern Aleppo Province as an alternative to deepening cooperation with the Syrian Democratic Forces (SDF) – a U.S.-backed coalition led by the Syrian Kurdish YPG, considered by Turkey to be a terrorist organization due to its links with the Kurdistan Workers’ Party (PKK). The U.S. airdropped ammunition and other supplies to vetted opposition groups in Mare’a on June 2 in a symbolic effort likely aimed at acknowledging these demands. The collapse of the Mare’a Line will nonetheless foreclose this alternative and instead drive the U.S. to deepen its current overreliance on the Syrian Kurdish YPG – setting the conditions for long-term ethnic conflict in the region and further limiting opportunities for partnership with Sunni Arabs in Northern Syria as part of the anti-ISIS campaign. In a reflection of this shift, the U.S. provided direct support to an SDF-led operation to seize the key cross-border transit hub of Manbij in Eastern Aleppo Province that began on June 1 despite long-standing reservations from Turkey regarding further Syrian Kurdish expansion along its border. The start of this operation despite these political tensions indicates that the U.S. may have already decided to abandon its support for Sunni Arabs in Northern Aleppo Province in favor of the Syrian Kurds – sacrificing long-term regional stability for short-term tactical gains against ISIS.