The leader of a Turkish opposition party has condemned the Turkish army operations against the  Kurdistan Workers’ Party (PKK) militants in the country’s southeast, saying Ankara is slaughtering citizens there.

“They (Turkish forces) committed a massacre in Cizre, and they don’t want to announce it,” Selahattin Demirtas, the co-chairman of the left-wing pro-Kurdish Peoples’ Democratic Party (HDP), told lawmakers from his party on Tuesday.

Over the past six weeks, the town of Cizre in the southeastern Sirnak Province has been under a curfew as part of the Turkish military operations against PKK militants.

People in the Turkish city of Istanbul held a demonstration on Monday to express their outrage at the Cizre curfew. Turkish riot police used water cannon to disperse the protesters.

As many as 100,000 of the 120,000 Cizre inhabitants have fled, according to Faysal Sariyildiz, the local MP from the HDP. A number of other citizens are still trapped in buildings in the restive town.

On Sunday, up to 60 wounded people, who had been sheltering in the basement of a building in Cizre, were killed during a military raid. Turkey claimed that high-profile PKK militants had holed up in the cellar.

Demirtas said some 70-90 people had taken refuge in the basement and a few other buildings in Cizre, which were coming under mortar fire.

“They are scattering the bodies on the streets, on ruined buildings,” he added.

Ankara’s anti-PKK campaign began in the wake of a deadly bombing in the southern Turkish town of Suruc last July. More than 30 people died in the attack, which the Turkish government blamed on Daesh Takfiri terrorist group.

After the incident, the PKK militants, who accuse the Turkish government of supporting Daesh, engaged in a series of what they view as reprisal attacks against Turkish police and security forces.