The Syrian army briefly captured a string of villages east of the Euphrates river Sunday before the territory was regained by the U.S.-backed Syrian Democratic Forces, Syrian state television said Sunday.
SDF forces, largely led by the Kurdish YPG militia, said Sunday that they launched a counterattack against Syrian troops, driving them far away from the four previously captured villages.
"Our forces regained the initiative," they said in a statement.
Earlier Sunday, state media outlet SANA said that the Russia-backed Syrian army captured four villages previously held by the SDF near the provincial capital Deir el-Zour, without providing a motive for the move.
The province, also called Deir el-Zour near the border with Iraq, had previously been held by Islamic State forces. Over the past year, the Syrian army has largely recaptured areas west of the Euphrates River, while the SDF have held areas east of the river.
Clashes between the two forces have been rare, with the Syrian army focused on regaining territory from IS militants west of the river.
Britain-based war monitor Syrian Observatory for Human Rights said that six SDF troops were killed and 22 injured in Sunday's fighting, adding that there were also casualties on the government side.
Islamic State has lost most of its territory in Syria and was declared defeated in Iraq last December. But its remnants are taking refuge across the vast border region between Iraq and Syria and carrying out periodic terror attacks.