DAMASCUS, Feb. 11 (Xinhua) -- At least four civilians were killed on Monday by a fresh U.S.-led airstrike in eastern Syria, state news agency SANA reported.

The airstrike targeted the Islamic State (IS)-held outskirts of the Baghouz town in the eastern countryside of Deir al-Zour Province, SANA said.

It is the latest in a string of U.S.-led airstrikes targeting the last IS-held pocket in the eastern Euphrates river region.

On Saturday, the U.S.-backed Syrian Democratic Forces (SDF) started the final attacks against the IS in the eastern Euphrates river region in eastern Syria.

The SDF has been on a crushing offensive to root out the IS from the eastern Euphrates region since last September.

The SDF managed, with the help of the United States, to defeat the IS in much of the eastern Euphrates region.

According to the London-based Syrian Observatory for Human Rights, more than 37,000 civilians, including dozens of IS militants, have fled the last IS-held pocket to areas controlled by the SDF in the eastern Euphrates region since last December.