Seven people, including five members of one family, have been killed in air strikes carried out by Syrian government jets on the Islamic State of Iraq and the Levant-held city of Raqqa, according to activists.

The strikes on Thursday targeted the districts of al-Jisr al-Qadeem, al-Mashlab, al-Handada al-Madaniya and buildings of the National Hospital and the municipality, in addition to al-Daraya district in southern Raqqa .

Syrian activists said 10 people, including three fighters from ISIL, were also killed during a government bombardment of a bridge on the Euphrates River, in Deir Ezzor in eastern Syria.

State news agency SANA reported that army units also destroyed a 30 metre tunnel and an ISIL headquarters in the al-Jubaila neighbourhood. It said gatherings of ISIL, including vehicles, were also hit in some neighbourhoods of Deir Ezzor

Raqqa, an ISIL stronghold, had come under intense Syrian government bombardment on Tuesday , killing 135 and injuring dozens, according to activists. The majority of the dead and injured were said to be civilians, including women and children.

Raqqa is the only provincial capital to be taken from the government since the outbreak of a 2011 uprising against President Bashar al-Assad.

The Syrian air force has stepped up strikes across Syria since a US-led coalition began attacking ISIL targets in Syria and also in neighbouring Iraq.

Syria's main political opposition, the National Coalition, on Thursday condemned recent strikes on Raqqa, calling them a "crime against humanity" in a statement published on its website.