US-led airstrikes killed at least 35 civilians when they hit residential buildings in Mayadeen, a Daesh-held town in eastern Syria near Deir ez-Zor, yesterday evening, the Syrian Observatory for Human Rights (SOHR) reported.
Head of SOHR, Rami Abdel Rahman, told AFP that the relatives of 26 Daesh fighters are among the dead, including Syrian and Moroccan citizens, nine other Syrian civilians including five children were also killed.
US-led strikes have inflicted an aerial bombardment on the town for two days. On Wednesday they killed 15 people, bringing the total death toll to 50 people in two days.
SOHR reported this week that 225 civilians were killed in coalition air raids between 23 April and 23 May, which is the highest monthly civilian death toll since the coalition began bombing Syria in September 2014.
Airwars, who track civilian casualties in the coalition's war on Daesh in Iraq, Syria and Libya, estimates that up to 355 civilians were killed in Iraq and Syria in April.