At least 9 people from the same family were killed on Wednesday when the U.S.-led coalition airstrikes struck the town of Tyiba in the eastern Deir Ezzor province, local activists said.
The victims included four children, and two women were the last victims of the U.S.-led airstrikes as the death toll reaches a total of 800 people in four months, local monitoring groups said.
The Syrian regime forces backed by Russian warplanes have also stepped up offensive on ISI-held areas in Deir Ezzor.
In the Western countryside, pro-regime militia, mostly tribesmen took three villages.
Also in eastern Syria, about 100 tribesmen fighting under pro-regime militia banner headed the desert from Qamishli airport on Monday as regime and allied forces wage major offensive against the Islamic State near the Iraqi border, sources said.
The Tribal Mobilization, or al-Hashad al-Ashaeri, was formed in April by regime forces in Hasaka province from the tribes youth. Ammar Johmani sources said the total number of the militia reached 3077 fighters.
Regime forces and Iran-backed Shiite militias pressed significant gains against ISIS in the desert, known as Badyia in the last few weeks along the Syrian-Iraqi border and strategic Tanaf crossing.
The regime army also took ground from ISIS in Raqqa province this week.