Turkish President Recep Tayyip Erdoğan said on Wednesday Turkey had the legitimate right to act again if the terrorists are not cleared from its border with Syria, where it has carried out several military operations to remove the terror elements out of the region in the last four years.
"If the terrorists here are not cleared as we were promised, we have the legitimate right to mobilise once again," Erdoğan said in a speech to the ruling AK Party lawmakers in the parliament.
In an offensive a year ago, with the support of Syrian opposition forces, Turkey liberated a 120 km (75 mile) stretch of border territory in northeast Syria from the YPG/PKK terrorists.
Erdoğan also voiced concern about the situation in northwest Syria's Idlib region, which was the scene of heavy fighting between pro-Assad regime forces and Turkey-backed Syrian National Army [SNA] until Ankara and Moscow reached a ceasefire deal in March.
On Monday, air strikes on a camp in northwest Syria run by SNA forces backed by Turkey killed at least 35 people and wounded scores, a war monitor and a rebel source said.
"The attack by Russia on (Turkey-backed) Syrian National Army forces in the Idlib region shows that lasting peace in the region is not wanted," Erdoğan pointed out.
A truce at the start of the year brought an end to a Russia-backed Assad regime offensive that had killed thousands of Syrian civilians and displaced almost one million people.
It was one of the worst humanitarian crises of Syria's nine-year civil war.
The last major Syrian opposition stronghold covers around half of Idlib province as well as slivers of adjacent provinces.