GENEVA (Reuters) - About 2,000 people were killed and entire neighborhoods razed in southeastern Turkey in 18 months of government security operations characterized by massive destruction and serious human rights violations, the United Nations said on Friday.

The U.N. human rights office said in a report on the period July 2015-December 2016 that up to 500,000 people, mostly Kurds, had been displaced, while satellite imagery showed the “enormous scale of destruction of the housing stock by heavy weaponry”.

U.N. investigators documented human rights violations including killings, disappearances and torture, often during curfews lasting several days at a time.

U.N. human rights chief Zeid Ra’ad al Hussein said in a statement that Turkey, which denied access for the investigators, had “contested the veracity” of the allegations.

“It appears that not a single suspect was apprehended and not a single individual was prosecuted,” Zeid said, adding an independent investigation was urgently needed.

Zeid’s spokesman, Rupert Colville, said an investigation could be international or Turkish but must be independent and impartial. The U.N. would continue investigating and might publish reports on Turkey every three months or so, he said, adding that security operations were continuing sporadically.

In a written statement, the Turkish Foreign Ministry said the report was based on “biased, incorrect” information and was “far from professional”.

“We do not accept the unfounded allegations in the report which correspond exactly to the terrorist group’s propaganda,” it said, adding the report was a clear violation of the impartiality and objectivity required of U.N. representatives.

It was referring to the Kurdistan Workers Party (PKK), which is the target of the Turkish security forces’ operations in the southeast. Turkey, the United States and European Union designate it as a terrorist group.

KILLINGS

Almost 800 of those killed were members of the security forces, and some of the other 1,200 may have been involved in action against the state, the report said.

Among the documented killings were those of up to 189 people trapped for weeks in basements in the town of Cizre in early 2016, without water, food, medical attention or power. They were killed by fire induced by shelling.

One woman’s family was given “three small pieces of charred flesh”, identified by DNA as being her remains. Her sister, who demanded legal action, was charged with terrorist offences, the report said.

Colville said the death toll figures came from the Turkish government.

“Definitely if the PKK have committed crimes and violations they need to be analyzed and exposed,” Colville said.

“The problem is because there has been this void, really, in investigation, nobody knows the scale of who has done what to whom and the precise details,” he said.

Although Zeid has been invited to Turkey, Colville said a U.N. investigative team needed to go first and it would be “absurd” to think Zeid’s visit could be a substitute.