The explosion took place near a middle school on early Monday at around 9.30 p.m.
Authorities reportedly said they were investigating whether the blast was caused by a mortar shell from Syria, whereas the mayor of Kilis province, Hasan Kara told Turkish private NTV news channel that the shells were "most probably" fired from the south.
Some media reports suggested that there were three shells fired, which landed on the Eyüp Gökçeimam middle school's garden [located about 10 km away from the Syria-Turkey border] and on empty land nearby, but the mayor Kara said, there was not precise information as to the number of the shells that were fired.
"We think that more than two shells were fired. It seems that they came from the south [Syria]," he said.
Kara further stated that one of the injured was in critical condition, and education services at all nearby schools were suspended.
Several rescue teams and ambulances were dispatched to the school amid reports that the province governor Süleyman Tapsız was also present in the area.
An Anadolu Agency video showed blood stains in the school's entrance hall and a small crater in the school's garden.
The force of the blast seems to have splintered the trunk of a tree and severely damaged a vehicle.
Last week, Turkey was hit by a suicide bomber who killed ten tourists in Istanbul as well as a car bomb detonated outside a police station in Diyarbakır province, which killed six. The latter was carried out by PKK terrorist while the Istanbul attack has been blamed on Daesh.
Source: Daily Sabah