Deir ez-zor: The Syrian Democratic Forces (SDF) announced the killing of five of its fighters in a surprise attack launched by ISIS members on one of its checkpoints in the eastern countryside of Deir ez-Zor last Thursday evening. The attack highlights the ongoing threat posed by ISIS despite its territorial defeat in Syria over six years ago.

According to National Iraqi News Agency, this attack is part of a series of operations carried out by ISIS in an attempt to revive its activities. The SDF, which is the most prominent local partner of the US-led international coalition, fought decisive battles alongside the coalition that led to the fall of the so-called ISIS “caliphate.” Key battles included the battle of Raqqa in 2017 and the battle of Baghouz in March 2019, marking the official declaration of ISIS’s defeat on the ground.

However, ISIS has since shifted to using sleeper cell tactics, exploiting the rugged terrain of the Syrian Badia and security tensions in and around Deir ez-Zor. Security data indicates that the governorate has recorded 114 ISIS attacks since the beginning of 2025, compared to 60 preemptive operations executed by the SDF in cooperation with the coalition.

This latest attack occurs as the tenth anniversary of the first major confrontation between the SDF and ISIS, during the siege of Kobani (2014-2015), approaches. This confrontation marked the beginning of the SDF’s rise as a major player with Western air support and was a turning point in the fight against ISIS.

In recent years, the SDF has launched several significant security operations to pursue remnants of ISIS. These include “Deterrence of Terrorism” (2020), “Al-Jazeera Thunderbolt” (2022-2023), and the “Raqqa Martyrs’ Revenge” operation, which led to the arrest of prominent ISIS leaders.