Syrian activists say government warplanes have carried out airstrikes that killed at least nine people and wounded dozens in an eastern town held by the Islamic State group.

Two activist groups reported Monday's strikes in the town of Mayadeen, giving different casualty tolls.

The Britain-based Syrian Observatory for Human Rights says 15 died, including three children. It says the death toll is expected to rise as some were critically wounded.

An anti-IS network called "Deir el-Zour is being Slaughtered Silently" said nine people died. The group says IS has been calling on people through mosque loudspeakers to donate blood to help the wounded.

Both activist groups said the airstrikes were carried out by Syrian government warplanes, which have been targeting IS-held areas over the past months, killing scores of people.