BEIRUT - At least 12 people, most of them students, were killed in an air strike that hit a secondary school in the rebel-held Syrian city of Raqqa on Sunday, activists said.
Fighting continued in provinces across the country including in the outskirts of the capital Damascus, where rebels staged an assault that a monitoring group said killed at least 19 government fighters late on Saturday.
Raqqa in northeastern Syria has been under the control of insurgents fighting to oust President Bashar al-Assad since March but the city remains subject to regular aerial bombardment by government forces.
The British-based Syrian Observatory for Human Rights, a monitoring group with a network of opposition sources across the country, said the death toll was at least 12 but that the number was likely to rise because some people were critically wounded.
Opposition activists based in Raqqa, a city of around 250,000 people, published a list of 14 people they said were victims of the strike on the school and said there were more than 30 others wounded.
Videos posted online by activists showed the bloody and charred remains of bodies said to have been from the air strike in Raqqa. Some of the victims appeared to be young men, possibly in their teens.
Fighting also continued in the southern Deraa province, a day after rebels in that area - including the al Qaeda-linked Nusra Front - seized a former customs post on the southern border with Jordan.
On the outskirts of the capital, an attack by rebels on military bases in the Qalamoun area killed at least 19 government fighters and wounded dozens of others, the Observatory said.
More than 100,000 people have been killed in Syria's conflict, which started as a peaceful uprising in March 2011 and turned into a civil war after a violent government crackdown on civilian demonstrators.
Reporting restrictions make it difficult to independently verify events inside Syria.