A warplane flies over the main road leading to Deir al-Zour City in east Syria Sept. 11, 2017. (Xinhua/Ammar Safarjalani)

MOSCOW, Sept 21 (Xinhua) -- The Russian Defense Ministry warned on Thursday the U.S. Armed Forces Command that it would not tolerate shelling attacks against the Syrian government troops from areas controlled by U.S.-backed opposition.

"Firing positions in these areas will be immediately suppressed by all available means of destruction," Defense Ministry spokesman Maj.-Gen. Igor Konashenkov said.

He said the Syrian government troops continued their offensive operations to destroy the last stronghold of the Islamic State (IS) terrorist group in the vicinity of the city of Deir al-Zour in northeastern Syria. Some 85 percent of the area is free from the IS and the whole city could be liberated within a week.

However, according to Konashenkov, the U.S.-led international coalition and the Kurdish-led Syrian Democratic Forces (SDS) stopped the operation to free Raqqa, the de facto capital of the IS.

Russian drones recorded the transfer of SDS militants from the province of Raqqa to the northern regions of Deir al-Zour province, but they did not record any clashes between the SDS and the IS.

However, they recorded two cases of massive mortar fire and launch of rockets against the Syrian troops from the areas on the eastern bank of the Euphrates River, where SDS militants and U.S. Special Forces operated, Konashenkov said.