The Britain-based Syrian Observatory for Human Rights and the DeirEzzor 24, an activist collective, said the fighting concentrated west of the eastern village of Baghouz near the Iraqi border that the extremists lost earlier this week.
U.S.-backed Kurdish-led fighters of the Syrian Democratic Forces have captured most of the area that was once controlled by IS on the east banks of the Euphrates River and the extremists now only control two villages. More than 20,000 civilians have fled the IS-held area and hundreds of militants surrendered since SDF began its offensive on Sept. 10.
The extremists are likely to lose the areas they control in Deir el-Zour in the coming few weeks as SDF fighters press their offensive under the cover of airstrikes by the U.S.-led coalition. Rami Abdurrahman, the Observatory's chief, said Thursday's fighting left 34 militants and 16 SDF fighters dead. He added that 21 IS gunmen were taken prisoners.
DeirEzzor 24 confirmed fighters from both sides were killed without giving a number. Earlier on Thursday, a bomb exploded in the capital Damascus causing property damage but no casualties, Syrian state media reported.
Syrian TV said the explosive was placed inside a car in the Adawi neighborhood. The Russian Embassy is located several hundred meters (yards) away. There was no immediate claim of responsibility. The bombing came two days after an explosion at a busy intersection in the coastal city of Latakia that killed a civilian and wounded 14 others.
Last week, a bomb also exploded in Damascus without inflicting casualties. The Syrian capital has been relatively safe since government forces captured last year all rebel-held neighborhoods and suburbs of Damascus.
Also on Thursday, In the northern town of Al-Bab, which is controlled by Turkey-backed opposition fighters, a motorcycle rigged with explosives blew up in the town's center. At least one person was killed and 11 wounded, according to the Observatory.
The opposition's Syrian Civil Defense, also known as White Helmets, said the blast killed three and wounded 12.