According to a security source, who spoke on condition of anonymity due to restrictions on talking to the media, the terrorists in Syria's northeastern Qamishli region opened harassing fire on Turkish soldiers at a border post in Nusaybin district of southeastern Mardin province.
It added Turkish armed forces immediately responded with tanks and howitzers and three terrorists were neutralized.
No casualties of Turkish soldiers were reported, it added.
On Saturday, Turkey launched Operation Olive Branch to remove PYD/PKK and Daesh terrorists from Afrin, northwestern Syria, on Turkey's border.
According to the Turkish General Staff, the operation aims to establish security and stability along Turkish borders and the region as well as to protect the Syrian people from the oppression and cruelty of terrorists.
The operation is being carried out under the framework of Turkey's rights based on international law, UN Security Council resolutions, and its right to self-defense under the UN charter and respect for Syria's territorial integrity, it said.
The military also said "utmost importance" is being placed on not harming any civilians.
Afrin has been a major hideout for the PYD/PKK since July 2012 when the Assad regime in Syria left the city to the terror group without putting up a fight.
Source: Anadolu Agency