Sixty-two Kurdish militants and two Turkish soldiers have been killed in four days of fighting across southeast Turkey as security forces ramp up operations against the Kurdistan Workers Party (PKK), security sources and the military said.

One Turkish soldier was killed on Saturday in clashes in Sur district, which has remained under a police curfew for the past two weeks, in the predominantly Kurdish Diyarbakir province.

One of two soldiers wounded in the border town of Cizre on Friday also succumbed to his injuries, the army said.

It said the number of Kurdish militants killed in four days of operations in Cizre and Silopi, near the Syrian and Iraqi borders, had risen to 62. The towns, both under curfew, are central targets in Turkey's latest anti-PKK offensive, in which media reports say 10,000 police and troops, backed by tanks, are taking part.

A two-year ceasefire between the PKK and Ankara fell apart in July, shattering peace talks and reviving a conflict that has afflicted the mainly Kurdish southeast for three decades, killing more than 40,000 people.

Although traditionally rooted in the countryside, the PKK has shifted its focus in recent years to towns and cities in the southeast, setting up barricades and digging trenches to keep security forces away.

Turkish President Tayyip Erdogan said this week that Kurdish militants would be "annihilated" in their trenches and houses and that the operations would continue until the area was "cleansed" of the militants and their barricades destroyed.

Peace talks between jailed PKK leader Abdullah Ocalan and the state ground to a halt early this year. The PKK is designated as a terrorist group by Turkey, the United States and the European Union.