At least nine civilians and 16 rebel fighters have been killed as security forces battle militants of the Kurdistan Workers Party (PKK) in Turkey's mainly Kurdish southeast, the army and the region's main political party said on Monday.
Violence has raged in the region since the collapse of peace talks last July aimed at ending a three-decade PKK insurgency.
Some of the worst clashes have been in the town of Cizre and the Sur district of Diyarbakir, the region's biggest city, where security forces have imposed a 24-hour curfew.
Ten of the 16 rebels killed on Sunday were in Cizre and six were in Sur, the military said on its website, adding that this brought the militants' total death toll in the two places to 749 since December.
A plainclothes police officer was also gunned down on Monday in the town of Yuksekova near the Iraqi border, media reported.
In the center of Istanbul, Turkey's largest city, police used water cannon and tear gas on Monday to break up a protest against the Cizre operations, witnesses said. Several people were detained, Dogan News Agency said.
Prime Minister Ahmet Davutoglu, speaking at a joint news conference in the capital Ankara with German Chancellor Angela Merkel, said the Cizre operations may draw to a close in the next few days.
"It is obvious that (the PKK) is implementing methods to destabilize cities in Turkey. In this regard, Cizre is a critical town, situated so close to the (Syrian) border, exploitable for weapons and terrorists to cross," he said.
The Peoples' Democratic Party (HDP), which has Kurdish origins and is the southeast's biggest party, named nine civilians who had been killed in Cizre since Friday, bringing the death toll to 127 civilians since December.
Davutoglu dismissed claims that civilians have been targeted and also denied reports that several wounded people had died after spending days stranded in buildings in Cizre.
Authorities had sent ambulances to collect the wounded - mainly PKK members - but the poor security situation had prevented them for reaching the hurt, he said.
The HDP said late on Sunday its lawmakers had not heard from a group of 15 wounded people, who have been sheltering in a basement in Cizre's Cudi district along with seven dead bodies for more than a week.
It said nine more people had died in a fire in a different basement in the area and that they had also not heard from wounded people there for the last two days.
The protest in Istanbul occurred after the HDP called for a march near Taksim Square, the city's tourism and transportation hub, to draw attention to the situation in Cizre, Dogan said.
Along with Turkey, the United States and European Union also designate the PKK as a terrorist organization.