The Syrian Army liberating the Deir ez-Zor region from terrorists is facing strong resistance and massive fire from areas where armed opposition groups and US forces are stationed, the Russian Defense Ministry said.

The Syrian Army continues to liberate the Euphrates valley to the east of Deir ez-Zor with the help of the Russian Air Force, the statement from the ministry says, adding that the government forces have already retaken more than 60 square kilometers on the left bank of the Euphrates from Islamic State (IS, former ISIS/ISIL).

The Syrian Army, however, faces resistance not only from jihadists, but also apparently from US-backed armed opposition groups, according to the statement

“According to the reports of the Syrian Army commanders, the most vicious counterattacks and massive shelling are launched from the northern [part of the region] controlled by the ‘Syrian Democratic Forces’ (SDF) and the US special forces that were deployed to the area to allegedly ‘lend medical assistance’ to these militants instead of liberating Raqqa,” the Russian Defense Ministry’s spokesman, Major General Igor Konashenkov, said.

He added that the Syrian Army also faced difficulties as it cut across the Euphrates River, where the water level surprisingly rose within several hours. Such water-level changes could only be the result of a deliberate flush at the dams that are also currently controlled by the armed groups backed by the US-led coalition, the major general said.

“As the final defeat of Islamic State [IS, formerly ISIS/ISIL] in Syria draws near, it becomes increasingly more evident who really fights Islamic State and who just imitates a fight for three years,” he said. “Even if the US-led coalition is not willing to fight terrorism in Syria, it should at least not prevent those who really do that consistently and effectively [from fighting terrorist groups].”

The eastern Syrian city of Deir ez-Zor was besieged by Islamic State for about three years. The blockade was lifted in early September by Syrian government forces, which brought relief to tens of thousands of people trapped in the city.

However, the liberation of Deir ez-Zor also intensified the race between legitimate Syrian government forces and the US-backed SDF umbrella group for control the oil-rich Deir ez-Zor province.

Following Damascus’ strategic victory, and while its forces continue to mop up pockets of IS resistance in the west of the city, the US-backed SDF announced a separate offensive east of Deir ez-Zor. SDF forces raced to Deir ez-Zor, which lies only 140km southeast of Raqqa, where the US-led coalition is conducting its main offensive against IS.