The Kurdish-led, and US-backed, Syrian Democratic Forces (SDF) moved reinforcements to the province of Deir Ezzor in Syria for continued fighting on Tuesday. In eastern Syria, illegally occupied by American forces and their SDF partners, ethnic tensions have been boiling over and clashes have been erupting for weeks between the Washington-supported group and local Arab tribesman.

Arab gunmen, associated with tribal leader Ibrahim-al Hifl, took over at least three positions in the town of Ziban – located near the Iraqi border – on Monday, during which a number of SDF fighters were killed. The fighters’ ultimate aim is to entirely seize Ziban. According to the UK-based Syrian Observatory for Human Rights, over 20 Arab fighters were killed during the skirmishes.

Al-Hifl released a statement calling upon “all tribes” to help take the fight to the SDF “terrorists.” However, as of yet, the majority of the tribes have not joined his fight.

Syria’s largest oil fields are located in the town as well as hundreds of US occupation forces. Ancillary to Washington’s economic war against Damascus, the US controls most of the war-torn country’s oil and wheat resources. There are roughly 900 US troops and an undisclosed number of contractors embedded with the SDF.

The SDF encircled the area on Tuesday and began shelling the positions held by the Arab tribesmen. The Kurdish militia claimed it allowed civilians to evacuate before launching the assault. Amid the shelling, one civilian was reported killed.

This comes in the wake of a larger movement by the tribes resisting Kurdish dominance in the province, where fighters have expelled SDF forces from parts of north and east Deir Ezzor. The fighting started late last month when the SDF arrested the leader of the formerly US-backed Deir Ezzor Military Council (DEMC), Abu Khawla. Since then, roughly 100 people have been killed.

The SDF has accused Damascus of being behind the unrest and instability. Although, the local Arab population in Deir Ezzor have long resented their impoverishment and political repression under Kurdish rule in the territory occupied by the US forces.

In Deir Ezzor, Damascus controls the area west of the Euphrates River, while Washington and their SDF proxy occupy Deir Ezzor east of the river. The Kurdish-led forces have accused the Syrian government of allowing the Arab militiamen to cross the Euphrates River.

The province’s residents complain about the Kurdish authorities’ corruption and say they have not received their fair share of the revenues generated by their province’s oil fields.

The New Arab reports that analysts have noted the perceived alignment between some tribal leaders and the Syrian government has caused divisions between members of the tribes and their leadership.

Robert Ford, the former US ambassador to Syria, has remarked that this current violence should not have surprised policymakers. “Anyone who was watching the deteriorating situation in Deir Ezzor wouldn’t have been surprised by this,” Ford recently told Middle East Eye.

He added, “Arab grievances against the SDF go back years. Instead of the US addressing those concerns and moving Kurds out of Deir Ezzor and bringing in local Arab leaders, it sat on its hands.”