“The violence in northeast Syria must cease,” the coalition said in a statement, saying that “distractions” from fighting IS sleeper cells risked a resurgence of the group.
Clashes broke out on Sunday after the Kurdish-led Syrian Democratic Forces arrested Ahmad Al Khubail, alias Abu Khawla, who headed its Deir al-Zor Council.
The SDF said Abu Khawla was arrested and dismissed from his post for complicity in multiple crimes, including drug trafficking and failing to address the looming ISIS threat in the eastern province of Deir al-Zor.
The province is home to several large Arab tribes and Abu Khawla’s arrest sparked clashes between them and the SDF. At least 40 fighters from both sides and another 15 civilians have been killed in the violence, according to local sources and witnesses.
The US-led coalition helped the SDF - which includes a smaller Arab component - oust IS from swathes of territory in northern and eastern Syria over the last seven years.
IS lost its last territorial bastion of Baghouz, which lies in Deir al-Zor, in 2019 to the SDF. ISIS still operates sleeper cells across parts of Syria and have waged hit-and-run attacks.