The Syrian Democratic Forces (SDF) tightened security measures in Syria’s northern city of Raqqa after foreign ISIS members escaped from jail in late August.
ISIS slogans were also painted on walls in Raqqa, raising concerns over the threat of the extremist group.
Residents discovered the slogans on Saturday morning, reminding them of the years they spent under ISIS’ brutal rule.
The group was defeated in Syria in 2019, but its cells remain active.
A security source told Asharq Al-Awsat that the SDF transferred dozens of foreign prisoners from al-Matahen jail to other more secure facilities following the jailbreak.
Two Russian, two Afghan and one Libyan ISIS members escaped al-Matahen in August.
American forces and the SDF managed to detain one of the Russians and the Libyan a day later. The rest are still on the run.
The source said the escape reminded the world and member countries of the anti-ISIS International Coalition of the threat of the extremist group and that its cells were still capable of carrying out attacks and striking fear in the local population.
Separately, the SDF announced on Saturday the arrest of 34 people suspected of joining ISIS cells.
The SDF carried out 16 security operations against ISIS in July and August, leaving at least five people dead.
Head of the SDF media center Farhad Shami told Asharq Al-Awsat that dangerous ISIS members were among the detainees.
They had planned and carried out several terrorist attacks in Kurdish-held regions, he revealed.
Among them was the chief official responsible for booby-trapping cars and another responsible for financing ISIS in Raqqa, he added.