Dozens of people have been killed and many wounded in a government air strike on a bakery in Syria’s central Hama province, opposition activists say.
The incident took place in Halfaya, a town recently captured by rebels.
If activists’ reports of 90 deaths are confirmed, this would be one of the deadliest air strikes of the civil war.
Syrian state TV blamed an “armed terrorist group” for the attack, saying the group had then filmed the incident to blame it on government troops.
Rebels have been fighting President Bashar al-Assad for 21 months, with opposition groups saying more than 44,000 people have been killed.
The latest violence comes as the joint United Nations-Arab League special envoy on Syria, Lakhdar Brahimi, arrived in Damascus to discuss ways to end the unrest.
‘Women and children’
One activist in Halfaya, Samer al-Hamawi, told Reuters news agency: “There is no way to really know yet how many people were killed. When I got there, I could see piles of bodies all over the ground.
“We hadn’t received flour in around three days so everyone was going to the bakery today, and lots of them were women and children. I still don’t know yet if my relatives are among the dead.”
Unverified video footage purportedly of the incident’s aftermath showed graphic images of bloody bodies strewn on a road outside a partially destroyed building.
Rescuers were trying to remove some of the victims buried beneath piles of bricks and rubble.
Several badly damaged motorbikes could be seen scattered near the site of the attack which had drawn a number of armed men to the area.
The UK-based activist group, the Syrian Observatory for Human Rights (SOHR), said more than 50 of the wounded were in critical condition and the death toll could rise.
Rebels of the Free Syrian Army have been making a concerted push recently to take areas of Hama province.
Five days ago they declared Halfaya a “liberated area” after taking over army positions there.
The BBC’s Jim Muir in Beirut says the rebels want to take control of the whole of Hama and link up the territory they control. As has happened many times before, he says, the government has hit back with massive firepower at the areas it has lost.
The SOHR said there had been other air strikes on Sunday, including one on the town of Safira in northern Aleppo province, which killed 13 people.
The Observatory also reported that jets had struck the town of Saqba, just north of Damascus.
It said more than 180 people had been killed across the country on Sunday.
The SOHR is one of the most prominent organisations documenting and reporting incidents and casualties in the Syrian conflict. The group says its reports are impartial, though its information cannot be independently verified.”
Fighting near Damascus airport forced the special envoy – on his third trip to Syria since taking the post – to arrive overland from neighbouring Lebanon.
He is expected to meet Syria’s foreign minister and President Assad.
However, Mr Brahimi has made little progress on a peace process so far and it is unclear what new ideas he may be bringing.
Our correspondent says the rebels now have a clear sense of victory and will not call off their attacks while they feel success is imminent.
He says the rebels’ primary demand is for President Assad to go and, should that happen, the international community is hoping there may be a chance for negotiations for a peaceful transfer of power.