The strike also killed three members of IS, which controls the town, the monitor said.

Earlier in the day, a US-led coalition strike killed seven civilians, including a child, in the village of Husseinyeh, the monitor said.

The US-led coalition has been carrying out air strikes against IS in Syria since 2014 and is providing air support for a Kurdish-Arab alliance advancing on the militant bastion of Raqa.

Last month, the coalition said its campaign against IS in Syria and Iraq had unintentionally killed at least 220 civilians, but monitors say the real number is far higher.

Most of the oil-rich province of Deir Ezzor, in Syria's east, is held by IS, including parts of the provincial capital, Deir Ezzor city.

The militants have besieged the remaining government-held parts of Deir Ezzor city, trapping civilians inside with limited access to supplies.

More than 320,000 people have been killed in Syria since the conflict began with anti-government protests in March 2011.