BEIRUT (Reuters) - At least nine 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.

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.

Opposition activists based in Raqqa, a city of around 250,000 people, published a list of 13 names they said were victims of the strike on the school and said there were more than 30 others wounded.

The Britain-based Syrian Observatory for Human Rights, a monitoring group with a network of sources across the country, said the death toll was at least nine but that the number was likely to rise because some people were critically wounded.

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.

(Reporting by Alexander Dziadosz; Editing by Mark Heinrich)