Turkey Syria border
Turkish Army tanks drive to the Syrian Turkish border town of Jarabulus Bulent Kilic/ AFP

Turkish air strikes over a period of 24 hours have killed at least 88 civilians in the Islamic State (Isis) stronghold of al-Bab in northern Syria, a UK-based monitor said.

"Eighty-eight civilians have been killed in 24 hours," the head of the Syrian Observatory for Human Rights, Rami Abdel Rahman, said. It is reportedly the bloodiest attack by Turkish troops that his monitoring group has recorded since Ankara began its campaign in Syria in August, Rahman added.

A wave of air strikes hit al-Bab on Thursday, (22 December) claiming the lives of 72 people, including 21 children, the Observatory said on Friday. The bombing reportedly continued on Friday, killing another 16 civilians, including three children.

For weeks, Turkey's forces along with their rebel Syrian allies, have been trying to gain control of al-Bab, which is located around 25 km of the north Syrian border. On August 24, Turkish troops made their way into Syria to support pro-Turkey Syrian rebels to eliminate Isis extremists as well as Kurdish militants on the border.

Isis released a video on Thursday that claimed to show two Turkish soldiers being burnt alive, after which Turkey pledged to respond. Turkish troops conducted air raids to back the ground operation in Syria but authorities stressed that utmost care is taken to avoid civilian casualties.