Armed clashes persisted on Sunday, December 20, across Turkey's southeast, where an operation by Turkish forces intensified on the sixth day of a campaign that security sources said had resulted in the death of 110 Kurdish militants, Reuters reports.

Protests erupted in Istanbul and in Diyarbakir, the biggest city in the country's south east, with hundreds demonstrating against the military operations. Police fired tear gas and plastic bullets to disperse the crowds.

Most of the fighting took place in Cizre and Silopi, towns near the Iraqi and Syrian borders that have been under curfew for almost a week. Nusaybin and Dargecit in the border province of Mardin and the historical Sur district of Diyarbakir have also seen fierce battles.

Although rooted in the countryside, militants of the Kurdistan Workers Party (PKK) have shifted focus in recent years to towns and cities in the southeast, digging trenches and setting up barricades in streets to keep security forces away.

Security sources and residents said around 300 houses in Cizre had been damaged by the clashes and undetonated mortar shells lay inside buildings.

Electricity was cut in many neighborhoods in Silopi as power transformers were damaged. Food and drinking water were running scarce, residents said.