DAMASCUS, Feb. 16 (Xinhua) -- At least 24 civilians have been killed by Turkish shelling on Syria's northern city of al-Bab, a stronghold of the Islamic State (IS) group, a monitor group reported Thursday.

The killing of the civilians happened during the past 24 hours of Turkish shelling on al-Bab, and 11 children were among those killed, said the Syrian Observatory for Human Rights.

The London-based watchdog group said that the death toll of the recent Turkish attack on the city that started on Feb. 7 rose to 89 civilians.

The Observatory also denied claims that the city has fallen to the Turkish forces and allied Syrian rebels, adding that IS militants are still in control of the city.

While the Turkish forces were on an offensive on IS from the northern, western and eastern parts of the city, the Syrian army succeeded recently to besiege al-Bab from its southern edge, a move to prevent IS fighters from withdrawing toward other strongholds in the eastern province of Deir al-Zour, or the northern city of al-Raqqa, the de facto capital of the terror-designated group.