At least 48 people have been killed in a car bombing along a busy street in a Syrian rebel-held town near the Turkish border.
The Syrian Observatory for Human Rights put the death toll at 48, while rebel media put it at 60.
Rescue workers said the explosion in the border town of Azaz in the northern province of Aleppo was so large that nearly 100 were wounded and burned.
Many rebel fighters and civilians who were pushed out of Aleppo during a massive government offensive last year resettled in Azaz.
Locals said a rigged tanker caused the explosion and blamed Islamic State militants, who have carried out attacks in the town before.
The bomb went off early on Saturday afternoon outside a local courthouse and security headquarters operated by the opposition fighters who control the town, resident and activist Saif Alnajdi said.
"It hit the busiest part of the town," Mr Alnajdi said.
A medical worker speaking to local media said many charred bodies, and body parts mixed with bones and mud, were piled up in local hospitals.
The town has recently been targeted by so-called Islamic State.
So far nobody has claimed responsibility for the bombing, according to the Syrian Observatory for Human Rights.
At the tail end of last year, a new ceasefire deal was brokered between Turkey and Russia to try and end Syria's six-year civil war.
The fragile truce, which was welcomed unanimously by the UN Security Council, has been repeatedly violated since it began, with warring sides trading the blame.
Russia started withdrawing its military forces from the Middle Eastern country on Friday.