A suicide bomber attacked Syrian opposition fighters just outside the town of al-Bab on Friday (February 24th), killing 51 people and wounding many others, AFP reported.
The attack came just hours after Turkish-backed opposition fighters had hailed the town's capture from the "Islamic State of Iraq and the Levant" (ISIL).
The bomber blew up a vehicle packed with explosives outside an opposition command centre in the village of Susian, eight kilometres northeast of al-Bab, the Syrian Observatory for Human Rights said.
There was no immediate claim for the attack, but opposition fighters blamed it on ISIL, which had put up fierce resistance in al-Bab for weeks.
Field commander Abu Jaafar of the Mutasem Brigades said opposition fighters, Turkish soldiers, and civilians from al-Bab had called a meeting in Susian "to organise a security apparatus and set a plan for rebuilding al-Bab".
"This information reached the (ISIL) sleeper cells, which prepared a car bomb" that detonated at Susian around 8 a.m., he told AFP.
Separately, two Turkish soldiers were killed in a suicide attack in al-Bab on Friday as they were carrying out road checks, Prime Minister Binali Yildirim said.