A Turkish official says suspected Syrian Kurdish fighters have fired rockets from across the border, slightly wounding one person.

Gov. Mehmet Tekinarslan says four rockets struck the town of Kilis early Sunday, hitting two houses and an office. He says Turkish artillery returned fire. The attack came as dozens of Turkish jets pounded the Kurdish-run enclave of Afrin in northern Syria.

Afrin is controlled by a Syrian Kurdish militia that Turkey views as part of the Kurdish insurgency in its southeast. The militia forms the backbone of the Syrian Democratic Forces, the main U.S. ally against the Islamic State group in Syria.

The state-run Anadolu Agency says Turkey-backed Syrian forces have penetrated the enclave and are advancing.

Prime Minister Binali Yildirim says a Turkish ground offensive could begin Sunday.