ANKARA, Turkey (AP) — Turkey's state-run news agency says Turkish tanks have crossed into Syria as part of a military operation to free a border town held by the Islamic State group.

In its report Wednesday, Anadolu Agency did not say how many tanks had entered Syria. It based its report on unnamed military sources.

Private NTV television said as many as 20 tanks had crossed into Syria. It said clashes were taking place at the border.