A car bomb on Thursday killed 14 oil workers and six Syrian Democratic Forces (SDF) terrorists near a base used by U.S.-backed SDF in eastern Syria's Deir el-Zour, a war monitor said.

"The car bomb was detonated remotely in the village of Shheel" close to the Omar oil field acting as a base for the People's Protection Units (YPG)-dominated SDF, the Britain-based Syrian Observatory for Human Rights said.

Six SDF militants were also killed as they escorted the workers in vehicles from the oil field, it said.

Local media reports said the explosion targeted a vehicle carrying about 30 workers of the SDF-controlled Omar oil field.

U.S.-backed SDF mliitants captured the Omar oil field — Syria's largest oil field, located on the eastern bank of the Euphrates river — from Daesh terror group in October 2017.

Omar oil field lies some 10 km (6.2 miles) north of the town of al-Mayadin.

The YPG is the Syrian affiliate of the PKK, listed as a terrorist organization by Turkey, the U.S. and the EU. In its more than 30-year terror campaign against Turkey, the group has been responsible for the deaths of some 40,000 people, including women and children.

The U.S. has partnered with the SDF, predominantly led by the YPG, in its fight against Daesh terror group, despite warnings from Turkey against the repercussions of using one terrorist group to defeat another.

Almost all the territory in the east of the Euphrates River comprising some one-third of the territory of Syria, except for the Assad regime-controlled area near Deir el-Zour and the Daesh-held area near the Iraqi border, is controlled by the SDF. The SDF also controls the districts of Manbij and Tabqah on the right bank of the river.