Syrians gather at the site of reported air strikes by government forces on May 1, 2014 in the Halak neighbourhood in northeastern Aleppo.
Rocket fire by Syrian military helicopters killed at least Ten people in the northern town of Azaz on Tuesday, a monitoring group said.
The air raid came hot on the heels of hours of a rocket strike on the nearby town of Marea which killed 13 people, 10 of them children, on Monday night, the Syrian Observatory for Human Rights said.
The helicopter gunships opened fire on the eastern entrance to Azaz, a small town in Aleppo province near Syria's border with Turkey, on Tuesday morning, the Britain-based group said.
Elsewhere, state news agency SANA reported that a photographer with the Syrian military, Hassan Omran, had been killed by "terrorist fire" while accompanying troops in southern Daraa province.
More than 162,000 people have been killed in Syria since an uprising against the rule of President Bashar al-Assad erupted in March 2011. Nearly half the population has been displaced.