In a remarkable coup, ISIS managed to wrestle the legendary city of Palmyra from the Syrian Arab Army (SAA) on Sunday after assembling a massive jihadist fighting force in eastern Homs.

Between 4,000 and 5,000 Islamic State insurgents poured into Palmyra from several flanks, prompting the SAA to withdraw to more defensible positions west of the ancient city after initially fending off several assaults.

Stationed on the Palmyra front were approximately 1,000 SAA soldiers, including contingents of the National Defence Forces (NDF), the 11th Division, elements of the 18th Division along with the Shaheen Group (Tiger Forces branch).

Facing overwhelming ISIS numbers and an imminent threat of encirclement, these government forces found themselves forced to regroup on the western outskirts of the city.

In addition to capturing Palmyra city itself, the Islamic State also seized Palmyra Airbase, the Hayyan gas field, Al-Dawa village, and the Al-Bayarat area following other territorial gains over the past 48 hours.

Recently, the SAA deployed the bulk of its elite factions in the battle for Aleppo; in the meantime, thousands of ISIS fighters crossed the border from Iraq, narrowly escaping the battle for Mosul in order to spearhead the ongoing Palmyra offensive.

Effectively, with manpower utterly disproportionate between the warring parties, local SAA commanders had to choose between a full-scale tactical retreat or leaving outnumbered government troops to be slaughtered by the rapidly advancing jihadist militants. To little surprise, the SAA’s Palmyra command center opted for the former option.

Palmyra was otherwise liberated by the SAA in late March 2016 and strategically represented an important government salient which could have been utilized to relieve besieged government soldiers in the eastern city of Deir Ezzor.

A larger version of the map can be found here.