At least 35 people were killed in airstrikes carried out by US-led forces in eastern Syria, according to the Syrian Observatory for Human Rights.
The British monitor group further said that the airstrikes on Thursday targeted areas under the control of the Islamic State (IS) group in the city of Mayadeen in the countryside of Deir al-Zour province.
A day earlier, the SOHR said that 16 civilians were killed by US-led strikes on the northern city of Raqqa, the de facto capital of IS, just hours after 15 civilians got killed as a result of explosions of mines in Raqqs countryside.
Raqqa and Deir al-Zour have been the target of the US-led coalition, which is backing the Kurdish-led Syrian Democratic Forces (SDF) in their push against IS in Raqqa countryside and areas near Deir al-Zour.
As a result, civilian casualties have become falling on a higher rate recently with reports of civilian deaths due to the intensification of US-led strikes.
(With IANS inputs)