At least 25 civilians were killed and 28 were wounded in airstrikes in the Syrian city of Raqqa, a de facto capital of Islamic State (Isis) on Tuesday (21 June), an activist group has said.

Britain based Syrian Observatory for Human Rights said it was not able to verify who conducted the airstrikes. Another group Raqqa Is Being Slaughtered Silently (RBSS) blamed the bombings on Russian warplanes. It said that at least one air strike targeted places that are popular with foreign fighters – people who migrated to Syria to fight for the extremist group. The Raqqa group later tweeted that the death toll rose up to 32 and at least 150 were injured.

On Tuesday, the jihadist group recaptured large areas of territory it recently lost to Syrian forces loyal to President Bashar al-Assad. The observatory had reported that IS (Daesh) forces pushed back government forces some 40km from Tabqa, an area located west of Raqqa and has an air base and Syria's largest dam.

The Syrian government force's campaign to retake the IS stronghold began on 2 June. On Sunday, Syrian forces advanced to about 10km of the Tabqa base.

According to reports, there were airstrikes carried out elsewhere in Raqqa on 22 June but this time allegedly by the US-led coalition against IS. There were no reports of casualties from the airstrikes, but they reportedly damaged the city council building.

The US-led coalition on Tuesday said it carried out four air strikes in Raqqa, destroying an IS tactical unit, headquarters, finance centre and hitting two oil pump jacks.

On 22 June, in a separate development, President Assad appointed incumbent electricity minister, Imad Khamis as the prime minister-designate.