DAMASCUS, Sept. 11 (Xinhua) -- The U.S.-backed Syrian Democratic Forces (SDF) are making progress in battles against the Islamic State (IS) in the last stronghold of the terror-labeled group in Syria, a monitor group reported on Tuesday.

The SDF with the help of the U.S.-led coalition is advancing in the last IS-held pocket on the eastern bank of the Euphrates River in the eastern countryside of Deir al-Zour, following 24 hours of the beginning of the wide-scale assault in that area, according to the Syrian Observatory for Human Rights.

The watchdog group said the battles took place on the frontline of the towns of Baghour and Hajin.

The SDF advanced and captured the western and northern parts of the Hajin town, which is considered one of the most important bastions of IS in the pocket that extends from Hajin to Baghour through the towns of Soseh and Shafeh.

The clashes are coupled with intense shelling by the U.S. coalition and the SDF in tandem with airstrikes from the coalition on this IS-held pocket on the eastern Euphrates.

The observatory, which says it relies on a network of activists on the ground, said 23 IS fighters have been killed in the first 24 hours of the SDF operation.

The town of Hajin has become empty of its residents, who fled to remote areas as a result of the shelling and military operations.

The SDF has also captured 29 IS fighters and their families in the desert of Deir al-Zour while attempting to flee toward the Iraqi border.

The SDF with the help of the U.S.-led coalition has been fighting in areas on the eastern side of the Euphrates river until besieging the IS in the last pocket there.

The operation is part of the U.S.-desired sway in that oil-rich region in Deir al-Zour.

The Syrian government has for long slammed the "illegal" operations in Syria as the coalition entered the course of the Syrian war in 2014.

Government officials have charged that the United States is ostensibly fighting the IS but in fact they are trying to establish a base to secure their interest in eastern Syria, which explains their support to the Kurdish-led SDF.