A large explosion in the busy centre of a rebel-held town near Syria's border with Turkey killed around 20 people and wounded dozens on Saturday, a monitor, local resident, and opposition groups said.
The Syrian Observatory for Human Rights said at least 19 people, mostly civilians, were killed in the blast in front of a courthouse in the northern Syrian town of Azaz.
Dozens more had severe injuries, said the Observatory, which monitors the violence in the country.
A resident and the opposition-affiliated Aleppo Media Centre said the death toll was around 20 and the explosion was thought to have been caused by a car bomb.
Syria's nearly six-year war has create a patchwork of areas of control across the country.
Azaz is a major stronghold of the Turkish-backed Free Syrian Army (FSA), an alliance of moderate rebel groups whose fighters have, with Turkish military support, pushed Islamic State militants out of the border area.
The explosion occurred near a government building in the town and was heard across the border in the Turkish town of Kilis, Turkey's privately-owned Dogan news agency.
It said preparations were being made to receive casualties in Kilis hospital.
In a round-up of its military operations over the last 24 hours in support of rebels in northern Syria, the Turkish military said on Saturday that 21 Isis militants had been killed in clashes.
Turkish warplanes destroyed buildings and vehicles in air strikes on 12 Isis targets, it said.
Reuters
