Turkish President Recep Tayyip Erdogan said Thursday his country is gearing up to “clear” the Syrian side of its frontier in response to cross-border fire from ISIS, hours after around 30 militants were killed near the border.

Erdogan said Turkey was making the necessary preparations “due to the difficulties in Kilis.”

Kilis, a town in southern Turkey across the border from IS-held territory in Syria, has witnessed multiple rocket attacks this year which authorities blame on ISIS.

Cross-border fire from Syria has claimed 21 lives and wounded dozens of others in Kilis.

Turkish military sources said Thursday that Turkish artillery pounded ISIS targets in northern Syria overnight and the U.S.-led coalition carried out air strikes, killing 28 militants near Kilis.

The artillery strikes near Kilis, north of the Syrian city of Aleppo, started at about 8 p.m. (1700 GMT) and ended in the morning, the sources said.

Intelligence reports had suggested the militants were preparing attacks, they said.

The air strikes destroyed a two-story building used by the militants as a base, along with 11 fortified defensive positions, said the sources.

The Turkish and coalition operations targeted an area about 10 km (6 miles) south of the border.

Erdogan said his country is prepared to act alone. He complained Turkey has not received the desired support from its allies.

He said on Wednesday that Turkey’s armed forces had killed 3,000 ISIS fighters in Syria and Iraq, where Turkish soldiers are training local forces to fight the insurgents. He did not give a time frame.

Turkey is home to a strategic air base, Incirlik, which the U.S.-led coalition uses to launch bombing runs against ISIS militants.