(FNA) -- According to the Syrian Observatory for Human Rights -based in London-, the US-led coalition warplanes targeted one of ISIS jails in al-Mayadeen city in Eastern Deir Ezzur on Monday, killing at least 42 civilian inmates and detainees.
Also, 15 ISIS terrorists, including the guards and a number of imprisoned members, were killed in the attack.
Reports said that the number of the civilian victims will most likely rise due to the critical conditions of several wounded civilians.
The prison accomodated 100 inmates, including civilians and a number of ISIS members.
Also on Monday, local sources reported that over 20 civilians were killed or injured in the US-led coalition air raids on in Raqqa province.
The sources reported that the US-led coalition warplanes carried out several combat flights over different neighborhoods of Raqqa city to back up the Kurdish-led Syrian Democratic Forces (SDF), killing a child and injuring 12 others mostly women and children.
In the meantime, 8 civilians were killed and several more were wounded in another air raid of the fighter jets in Raqqa.
The Syrian Observatory for Human Rights said on Saturday that almost 500 civilians were killed in the US-led collation air raids in Syria last month.
It reported that 472 civilians, including 137 children lost their lives in the US-led coalition warplanes' attacks in Syria form May 23 till June 23.
Relevant reports said last Tuesday that over a dozen other Syrian civilians were killed in another US-led coalition air raid in areas near the border with Iraq.
"At least 12 civilians have reportedly been killed after US coalition fighter jets struck a number of targets in a village next to the Syrian-Iraqi border," eyewitnesses disclosed.
According to the report, the US-led anti-ISIS coalition warplanes have launched a series of air raids in Hasaka province. In one of the strikes, the bombers struck Tel Hayr village near the Syrian-Iraqi border, killing 12 people, all belonging to one family.
Meantime, the United Nations war crimes investigators reported that the US-led coalition's aerial back up for the SDF to take control of Raqqa from ISIS have thus far killed hundreds of civilians and displaced tens of thousands more.
The UN investigators said that intensified US-led coalition air raids on ISIS's strongholds in Raqqa are causing a "staggering loss of civilian life".