Four rocket projectiles fired from Syria struck a Turkish border town on Monday, killing three Syrian children and a Syrian man, officials and reports said.

A Turkish citizen and five other Syrians were also wounded in the rocket fire that hit the southern town of Kilis, where the Syrian refugee population outnumbers the local population, the governor's office said.

One of the projectiles exploded near a middle school in the town, injuring the 40-year man who was herding sheep as well as a 14-year-old boy, the state-run Anadolu news agency reported. The man later died of his wounds in a hospital.

Another projectile hit the roof of a two-story building, Anadolu reported. It was not immediately clear if the three Syrian children were killed in that incident.

Two other projectiles earlier hit an olive grove and a building used to store hospital oxygen units but caused no casualties.

The deaths raise the number of fatalities caused by rocket fire in Kilis in the past two weeks to five. The town has witnessed an almost daily salvo of rocket fire from Islamic State-controlled territory in Syria.

Turkish artillery units systematically retaliate for rockets or shells that land on Turkish territory in line with its rules of engagement. Last week, jets belonging to the U.S.-led coalition against the IS attacked the militants' positions in Syria along the border with Turkey, in an apparent response to the rocket fire on Kilis.

The defense minister said last week that Turkish retaliatory strikes against the rockets and shells fired into Turkey had killed 362 militants and wounded 123 others so far this year.