Activists say the American-led coalition attacking a jihadi group in Syrian has launched airstrikes on its positions including wheat silos in the country's east.

The Britain-based Syrian Observatory for Human Rights says the strikes targeted compounds for the Islamic State group in the central province of Homs and the northern region of Raqqa.

The Local Coordination Committees, another activist group, said the Saturday strikes hit the eastern province of Deir el-Zour as well as Raqqa.

The LCC also said the coalition targeted wheat silos west of the eastern city of Deir el-Zour.

The coalition, which began its aerial campaign against Islamic State fighters in Syria early Tuesday, aims to roll back and ultimately crush the extremist group, which has created a proto-state spanning the Syria-Iraq border.