Curfews, street barricades and armed police everywhere: the unrest in Turkey's mainly-Kurdish southeast is likely to have an impact on the upcoming election but it also risks spelling a defeat for democracy.

Nestled near the border with Syria and Iraq, the city of Cizre became a symbol of the bloody conflict after violent clashes between Turkish security forces and the youth wing of the Kurdistan Workers Party (PKK) last month.

Turkish authorities on Monday lifted a curfew in the mainly Kurdish southeastern city of Cizre after reimposing it for 12 hours following a deadly nine-day military lockdown, the regional governor's office said.

The curfew, enforced as the army battles Kurdish militants, had first been put in place on the evening of September 4 and then lifted last Friday after nine days amid concerns of a humanitarian crisis.

Turkey on Sunday restored an open-ended curfew in the mainly Kurdish southeastern city of Cizre to catch Kurdish militants, just two days after ending a hugely controversial identical order.

The new measure came into effect at 1600 GMT after thousands of Cizre locals turned out for the funerals of 16 people killed in violence during the previous nine-day curfew that also left several buildings in ruins.

Three policemen were killed by Kurdish militants on Sunday in two separate attacks in Turkey's southeast, security sources said, as the authorities imposed new curfews in the battle against the rebels.

Two officers were killed and five wounded on a highway outside the city of Sirnak in a car bomb attack carried out by the outlawed Kurdistan Workers Party (PKK), the sources told AFP.

Two people were killed and three injured Saturday in clashes between Kurdish rebels and a Sunni Islamist group in southeast Turkey near the Syrian border, a local governor's office said.

Tensions have escalated in the town of Cizre since Friday night when the Sunni Muslim Huda-Par group attacked tents belonging to rebels of the outlawed Kurdistan Workers' Party (PKK), a security source told AFP.