Fierce fighting is taking place in Syria’s second city, Aleppo, say reports, as rebel fighters try to take control from the army.
Pro-government troops are bombarding the city with shells and rocket fire, and there are reports that helicopter gunships are being used.
Activists say at least 33 people have been killed across the country on Tuesday so far.
Nine of those are reported to have died during a prison revolt in Aleppo.