A car bomb has ripped through a busy commercial district in a rebel-held Syrian town along the Turkish border, killing nearly 50 in a huge explosion that damaged buildings and left rescuers scrambling to find survivors.
Rescuers and doctors said the explosion was so large there were nearly 100 wounded and burned. Over 50 wounded were transported to the Turkish border town of Kilis for treatment, as local hospitals couldn't cope.
There was no immediate claim of responsibility.
Locals said a rigged tanker caused the explosion and blamed Islamic State militants, who have carried out attacks in the town before. IS has been increasingly pressed in Syria and Iraq, and has escalated its attacks against Turkey.
Azaz, only a couple of kilometres from the Turkish border, is a key town on a route used by opposition fighters moving between Syria and Turkey, and is a hub for anti-government activists as well as many displaced from the recent fighting in Aleppo city.
The bomb went off early Saturday afternoon outside a local courthouse and security headquarters operated by the opposition fighters who control the town, resident and activist Saif Alnajdi told The Associated Press from Azaz.
"It hit the busiest part of the town," Mr Alnajdi said, referring to the administrative part of town.
A medical worker speaking to a local media outfit, al-Jisr, said many charred bodies, and body parts mixed with bones and mud, were piled up in local hospitals.
Rami Abdurrahman, the head of the Syrian Observatory for Human Rights monitoring group, said at least 48 people were killed, including 14 fighters and guards to the local courthouse.
He said the explosion was caused by a rigged water or fuel tanker, which explained the large blast and high death toll. The activist-operated local Azaz Media centre and Shabha Press put the death toll at 60, adding that search and rescue operations continued for hours after the explosion.
Mr Alnajdi said rescue workers were still working to identify and remove the bodies from the area, suggesting that the death toll was not final. He said some of the severely wounded were transported across the border into the Turkish town of Kilis for treatment.
Media activist Baha al-Halabi, based in Aleppo province and who gathered information from Azaz residents, said witnesses reported many unidentified bodies. Footage shared online showed a large plume of black smoke rising above the chaotic street with the sound of gunfire in the background as onlookers gathered around the site.