Syrian army warplanes have carried out a wave of attacks in the city of Raqqa, activists have said, with no specific figures on casualties. 

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Raqqa activists have told Al Jazeera that warplanes on Thursday carried out at least 11 air strikes on the city held by the Islamic State of Iraq and the Levant (ISIL).

It was not immediately clear what was hit in the attacks

The city is frequently targeted by planes belonging to the US-led anti-ISIL coalition, but strikes by the Syrian government are rare. Syrian government attacks typically concentrate on rebel-held areas of the country.

Raqqa is the self-declared capital of ISIL's so-called caliphate, which includes a vast area of land between Syria and Iraq. 

Medical sources in Raqqa told Al Jazeera that women and children were among those injured.

ISIL's media arm claimed the raids had killed at least 30 people and injured dozens of others. Pictures posted on Twitter by accounts affiliated with the armed group showed wounded men and children.

It was not clear, if any of the men shown were ISIL members or combatants.

'Defeating terrorism'

Syrian President Bashar Assad said in an interview with Russian media on Wednesday that that the US had refused to coordinate with his government in the fight against ISIL.

For the US officials, "if they cooperate with the Syrian army, this is like recognition of our effectiveness in fighting ISIL," Assad said.

He also said that his priority was "defeating terrorism" in Syria.

Russia is trying to convince the West of the need to work with Syria in the fight against ISIL.

Thursday's airstrikes on Raqqa coincided with a visit by the UN envoy to Syria, Staffan de Mistura, to Damascus.

De Mistura met with Foreign Minister Walid al-Moallem, who repeated to him that fighting terrorism was the Syrian government's priority, according to the state-run news agency SANA.

- With additional reporting by Al Jazeera