Eight children were among 11 civilians killed Monday in a Turkish artillery attack that hit near a school in a northern Syrian town in Aleppo province, a war monitor said.

The shelling on Tal Rifaat, controlled by local Kurdish fighters, took place as students were leaving the building and wounded 21 others, the Britain-based Syrian Observatory for Human Rights said.

Most of those killed in the attack were displaced from the Afrin region, which was captured last year by Turkish troops and their Syrian proxies, Observatory head Rami Abdel Rahman said.

Tal Rifaat, a strategic town located 20 km (12 miles) south of Turkey’s frontier, is the site of regular confrontations between Turkish-backed forces and Kurdish fighters they view as “terrorists.

Turkey threatened to launch a cross-border offensive to capture Tal Rifaat last year after taking Afrin from the U.S.-backed People’s Protection Units (YPG) militia.

But Russia intervened to stop the planned offensive.

In October, it said it agreed to work with Turkey to remove all YPG militia “elements and their weapons” from Tal Rifaat.

But in early November, Turkish President Recep Tayyip Erdogan said Kurdish “terror groups” had still not left.

Tal Rifaat is held by local Kurdish fighters displaced from Afrin, the Observatory head said.

Russian forces and regime troops are also currently deployed inside the town, Abdel Rahman added.

The town’s population was initially comprised mostly of Arabs and Turkmen, but Ankara’s Afrin offensive last year sent waves of displaced Kurdish families to the area.

Turkey in October launched a cross-border operation south of its frontier against Syrian Kurdish forces it views as terrorists.

In the two months since the operation began, it has established a so-called “safe zone” in a 120-km (70-mile)-long strip along its southern border, where it says it wants to resettle Syrian refugees.