The rapid advance of US-backed Syrian Kurdish fighters, who are taking advantage of Russian airstrikes in the region to seize territory near the Turkish border, has infuriated Ankara, which sees the insurgents as a terrorist organization. Turkey has been shelling YPG positions for days.
"Today our rules of engagement may be just about responding to an armed attack against our country, but tomorrow if necessary those rules can be expanded to cover every threat," Erdogan said in a speech broadcast live on television, Reuters reported.
"Nobody should doubt that. We will not allow the formation of a new 'Qandil' on our southern border," he said, referring to the Qandil mountains of northern Iraq, where the outlawed Kurdistan Workers Party (PKK) has bases.
Erdogan said ignoring the link between the Syrian Kurdish PYD and the PKK, which has fought a three-decade insurgency for greater Kurdish autonomy in Turkey's mainly Kurdish southeast, was a "hostile act".