Turkey should consider stripping supporters of terrorism of their citizenship, President Tayyip Erdogan said, adding that the government had "nothing to discuss with terrorists".
His comments on Tuesday, in a speech to a group of lawyers in the capital, Ankara, came a day after he ruled out a revival of peace talks with the outlawed Kurdistan Workers Party (PKK).
Turkey regards the PKK as a terrorist organisation.
"To prevent them from doing harm we must take all measures, including stripping supporters of the terrorist organisation of their citizenship," he said.
"These people don't deserve to be our citizens. We are not obliged to carry anyone engaged in the betrayal of their state and their people.
"Supporters [of terror] who pose as academics, spies who identify themselves as journalists, an activist disguised as a politician ... are no different from the terrorists who throw bombs.
"But like a wolf in sheep's clothing, they serve the same purpose as the members of the terror organisation. As a nation we need to be careful. No one must commit treachery against the state and the nation behind our backs."
Erdogan also vowed to stamp out the conflict in Turkey's mainly Kurdish southeast, at its deadliest in two decades, once and for all.
PKK tensions continue
Two members of the Turkish security forces were killed in fighting in the southeast on Monday, officials said.
The autonomy-seeking PKK abandoned its two-year ceasefire in July, reigniting a conflict that has claimed more than 40,000 lives, mainly Kurdish, since 1984.
The violence wrecked a peace process, spearheaded by Erdogan, that was seen as the best chance at ending one of Europe's longest-running insurgencies.
"We said 'resolution process', and they deceived us, their word cannot be trusted. That's over now, we are going to finish this off," Erdogan said in a speech to the state-run Red Crescent humanitarian organisation. It was aired live by TRT.
"The terrorists can choose two paths: surrender to justice or be neutralised, one by one. There is no third way left in Turkey. We tried that repeatedly in the past," he said, then denied rumours there had been recent contacts with the PKK.
Almost 400 soldiers and police and thousands of militants have been killed since July, Erdogan said last week.
Opposition political parties say between 500 and 1,000 civilians have also perished in the fighting, centred in towns and cities in the southeast, home to most of Turkey's estimated 15 million Kurds.
In the town of Nusaybin at the Syrian border, PKK fighters used a rocket launcher to fire on soldiers, killing one and wounding two others, security officials said.
In a separate attack, a member of the local village guard militia was killed while taking his children to a health clinic, they said.