Four rockets fired by jihadists in Syria slammed into the southern Turkish town of Kilis on Monday, April 18, killing four Syrians including three children in the latest deadly cross-border strike, officials said, according to AFP.

Kilis -- the only town in Turkey where refugees from the war in Syria now outnumber Turkish locals -- has been repeatedly hit by rocket fire from areas in Syria controlled by Islamic State (IS) jihadists in recent weeks.

"Four Syrians living in Kilis, including three children were killed," the Kilis governor's office said in a statement.

Five Syrian children and one Turkish citizen were also wounded by the rocket fire which hit the town centre in a two-hour period from 1130 to 1330 GMT.

The other fatality caused by the Katyusha-type rockets was a Syrian shepherd who was tending his flock close to a school that was hit, the Dogan news agency said, according to AFP.

The fire was confirmed to have come from an area in Syria controlled by IS, Dogan added.

Turkish armed forces hit back by firing mortar shells at IS targets inside Syria, the report said.

At least 10 people have now been killed so far in strikes on Kilis from Syria but this was the heaviest toll recorded so far in a single day.