ERBIL, Kurdistan Region of Iraq - The Kurdish-led Syrian Democratic Forces (SDF) said on Saturday that four of its fighters were killed while repelling a suspected Islamic State (ISIS) attack in eastern Syria’s Deir ez-Zor province, days after another jihadist ambush killed five SDF fighters. 

“Four of our SDF fighters were martyred while confronting a treacherous attack carried out by ISIS terrorist cells in the town of Abriha, east of Deir ez-Zor, following direct clashes that resulted in the elimination of one terrorist,” the SDF said in a statement. 

It follows another deadly ISIS attack on SDF positions on Thursday, also in Deir ez-Zor. Five SDF members were killed in that attack. 

These incidents also come amid a surge in ISIS attacks in northeast Syria since Bashar al-Assad’s fall, with the militant group seeking to exploit the instability in the region. The group primarily operates in the remote desert areas of Homs and Deir ez-Zor provinces.

SDF spokesperson Abjar Dawood on Monday stated that ISIS militants have carried out more than 150 attacks in northeast Syria since the fall of Assad’s regime in December 2024.

The Syrian Observatory for Human Rights, a Britain-based war monitor, reported on Saturday that at least 11 SDF members have been killed in less than 10 days.

“This escalation comes at a time when there are increasing indications that the organization [ISIS] is returning to its old tactics based on ambushes, assassinations, and surprise attacks,” the Observatory said. 

ISIS took control of swathes of Syrian and Iraqi territory in 2014, declaring its so-called caliphate with the Iraqi city of Mosul as its capital. They were territorially defeated with assistance from the US-led coalition forces in Syria in 2019.

The US-backed SDF functions as the de facto army of northeast Syria and currently controls one-third of the country’s overall territory.