BEIRUT - The Syrian Observatory for Human Rights said on Tuesday dozens of people were killed in an air strike believed to have been carried out by the US-led coalition on an Islamic State prison in eastern Syria.
The US-led coalition said it would look into the report.
The Observatory said the air strike took place on Monday at dawn, hitting a building in the town of al-Mayadeen that was being used as a prison. It said at least 42 people were killed, identifying them as prisoners of Islamic State.
Syrian state-run TV station al-Ikhbariya cited its correspondent in Deir al-Zor as saying coalition warplanes had destroyed a building in al-Mayadeen used as a prison by Islamic State. In a news bulletin flashed on screen, it said the building had been used as a prison for a "large number of civilians".