A spokesman for the U.S.-backed militia that controls Manbij said a terrorist attack on a checkpoint at the city’s entrance killed seven fighters on duty. A U.S. official said all the casualties were among members of the Kurdish-led Syrian Democratic Forces (SDF), Reuters reported.

Islamic State said in a statement that “caliphate soldiers attacked a checkpoint of the apostate PKK (Kurdistan Worker’s Party)” west of Manbij using machine guns and killed nine fighters.

The SDF on Saturday proclaimed the capture of Baghouz, Islamic State’s last territory in Syria, eliminating its rule over a self-proclaimed “caliphate”, but the jihadists remain a threat, with followers around the world.

“We cannot blame a specific side for this attack, but it is definitely linked to the proclamation of victory over Daesh (IS),” Manbij Military Council spokesman Sharfan Darwish said.

“The purpose of these attacks is to incite sedition. Also the parties troubled by the defeat of Daesh are trying to threaten stability in the area,” he told Reuters.

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