Syrian regime air strikes on Islamic State group stronghold Raqa have killed at least 95 people, while a delegation from President Bashar al-Assad's government has held talks with key ally Russia.
The bombing on Tuesday was the deadliest by Assad's air force in Raqa since Sunni extremist IS fighters seized control of the city last year and declared it their capital.
More than half of the dead were civilians, according to the Syrian Observatory for Human Rights.
It was unknown how many jihadists were killed.
Raqa was the first provincial capital to fall from regime control, and it was later overrun by IS which has used it as the capital of its self-proclaimed "caliphate" straddling Syria and neighbouring Iraq.
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The multi-sided Syrian conflict has killed more than 195,000 people and forced millions from their homes since it began three and a half years ago as an uprising against Assad's regime.
The government has in recent months stepped up its air strikes against IS-held towns in the north and east, with most of the casualties reported to have been civilians.
Raqa has also been the target of repeated air strikes by the US-led coalition fighting the jihadists.
Syria's exiled opposition National Coalition condemned the strikes as a "brutal massacre", warning that "many seem now convinced that Assad is the major beneficiary of the US-led coalition strikes" against the jihadists.
Meanwhile, a Syrian delegation headed by Foreign Minister Walid Muallem held talks with Assad's key ally President Vladimir Putin at his Black Sea retreat of Sochi on Wednesday.
But the content of the closed-door discussions was not revealed.
Ahead of the talks, Russia's foreign ministry said the issue of "mending the political process" would be high on the agenda.
Two rounds of UN-brokered talks were held in Switzerland in early 2013. Both ended without agreement.
After Wednesday's meeting, Russian news reports quoted Foreign Minister Sergei Lavrov as saying no new Geneva talks were possible at this time.
Amateur video footage distributed by activists in Raqa showed several bloodied bodies laid out on a street near an apparent bombing site, as an ambulance and aid workers rushed to the scene.
