Ankara: An anti-aircraft shell from Syria hit an empty room of a health centre inside Turkey, a private news agency reported Tuesday. No injuries were reported.

The shell pierced through a window of the health centre some 200 meters inside the Turkish border, in the town of Reyhanli and ricocheted five times before hitting a wall, the Dogan news agency reported. An investigation was launched into the incident, the agency said.

Forces of Syrian President Bashar Assad have been battling rebels near the town of Haram, in Syria's Idlib province, across the border from Reyhanli.

Ever since a shell fired from Syria on October 3 slammed into a Turkish border town, killing 5 civilians, Turkey has been firing into Syria in response to similar attacks.

More than 33,000 people have been killed in Syria since the uprising started in March last year.