DAMASCUS, May 9 (Xinhua) -- The U.S.-backed Syrian Democratic Forces (SDF) opened fire at protesters in eastern Syria on Thursday, killing seven of them, state news agency SANA reported.

Hundreds of protesters gathered in the town of Shahil in the northeastern countryside of Deir al-Zour Province against the practices of the SDF in the town, SANA said.

It's worth noting that the SDF controls areas in eastern Deir al-Zour after capturing them from the Islamic State (IS) militant group.

The Syrian government recently reaffirmed that all Syrian areas will return under the government control, urging the Kurdish-led groups, including the SDF, to choose the interest of Syria first.