Early on December 6, unknown gunmen attacked the U.S.-occupied Omar oil fields in the southeastern countryside of Syria’s Deir Ezzor, according to the Syrian Arab News Agency (SANA).

The state-run agency’s reporter in the eastern region said that the attack coincided with the arrival of U.S. military and logistic supplies to a base inside the fields.

“U.S. occupation forces responded with artillery strikes and fired illumination rounds,” the reporter said.

The Kurdish-led Syrian Democratic Forces (SDF) denied the SANA’s report claiming that the explosions heard near the oil fields were a result of live fire drills between its units and the U.S.-led coalition.

Unknown Gunmen Attack U.S.-Occupied Omar Oils Fields In Eastern Syria – Reports

The Omar oil fields are among the biggest in Syria. Prior to the Syrian war, the fields produced around 30,000 oil barrels per day. The remaining ISIS cells in the eastern region launched several attacks on the oil fields over the last year.

U.S. forces reinforced their positions in the al-Omar oil fields in the last two months as a part of Washington’s new plan to “guard” oil fields in eastern Syria. The highly questionable plan was widely seen as an attempt to pillage the war-torn country’s oil.