Twenty-eight civilians were killed in an air strike in Syria’s eastern province of Deir Ezzor, the Syrian Observatory for Human Rights said on Friday, according to Jerusalem Post. This was one of the last holdouts of the Islamic State group.

While the observatory could not identify who carried out the airstrikes, the Syrian state media accused the United States-led coalition against the Islamic State group of bombing the regime’s positions.

In June, at least 52 foreign fighters allied to the forces of Syrian President Bashar al-Assad were killed in overnight airstrikes near the country’s eastern border with Iraq. In February, the US killed 100 Syrian soldiers loyal to Assad in airstrikes in the province of Deir Ezzor after the troops allegedly started a coordinated assault on Syrian opposition forces.