At least 22 people have been killed in clashes in eastern Syria between the Kurdish-dominated Syrian Democratic Forces and a local armed group, the Syrian Observatory for Human Rights said on Tuesday.

“Sixteen fighters from the region and three members of the Syrian Democratic Forces (SDF) were killed in clashes in villages in the eastern part of Deir Ezzor province,” said the NGO, which is based in Britain and relies on a wide network of sources in war-torn Syria.

Three civilians, including two children, also lost their lives amid hostilities, according to the same source.

Backed by the US, the SDF spearheaded the operations that defeated the Islamic State (IS) in Syrian territory in 2019.

They control a semi-autonomous Kurdish zone in the north-east of the country, including large parts of Deir Ezzor.

The Deir Ezzor Military Council is a local Arab armed group that had allied with the SDF led by Ahmad al-Habil, also known as Abu Hawlah, who was arrested on Sunday in the city of Hasakah, according to the Syrian Observatory for Human Rights.

His arrest sparked tensions that erupted into clashes as SDF positions came under attack, the NGO explained.

The reason why Ahmad al-Habil was arrested is not clear, but the Syrian Observatory for Human Rights and an AFP source in the region said he is known to be involved in smuggling and has amassed a sizeable fortune over the years.

The Deir Ezzor Military Council guarantees security in some parts of the eponymous province, where mainly Arabs live.

The leadership of the semi-autonomous Kurdish zone governs the region through intermediaries – local political and military councils – to avoid displeasing the region’s tribes, almost all of whom are Arab.

“Actually it’s about settling scores,” said Omar Abu Laila, a local journalist.

“Corrupt commanders felt threatened after the arrest of Abu Hawlah and tried to turn the case into a tribal issue to protect themselves,” he added.

The SDF limited itself to announcing that it has been conducting an “operation to strengthen security” in Deir Ezzor province since Monday, against IS and “criminals involved in drug and arms trafficking.”