Prisoners at high-security units in the Netherlands are living in "inhuman" conditions, a new report by Amnesty International and the Open Society Justice Initiative has revealed.

The conditions at two Dutch terrorism prisons violate international human rights, the campaign group concluded in a report published on Tuesday (31 October).

More from IBTimes UK

Former detainees told Amnesty that they were routinely confined to their cells for between 19 and 22 hours a day and had little contact with others when they were allowed out. They said that they were under constant surveillance which prevented them from discussing private matters when family members visited.

Amnesty conducted 50 interviews and documented at least three cases of prolonged solitary confinement - 22 hours per day - which breaches international human rights standards.

Former prisoners at the high-security units also said that they were subjected to full-nudity body searches which they described as "humiliating" and "invasive".

Some of the prisoners held at the units were awaiting trial and were detained alongside those who had been found guilty of terrorism offences.

"Many of the measures routinely used in the terrorist units can unnecessarily isolate and humiliate people and as such violate The Netherlands' human rights obligations," said Doutje Lettinga of Amnesty International Netherlands. "Even a person who poses no proven security threat can be held in one of the country's harshest detention regimes."

Dutch authorities have stated their willingness to implement several reforms, but Amnesty and the Open Justice Society Initiative say the plans lack transparency and fail to properly address the human rights concerns in terrorist units.

"We welcome the openness of the authorities to consider positive changes to the terrorist units," said Jonathan Horowitz of the Open Society Justice Initiative. "But any reforms must be carefully designed and implemented to ensure maximum transparency and compliance with The Netherlands' human rights commitments. Security measures must not be excessive or arbitrary."

Horowitz added that the current conditions and the lack of reintegration opportunities carry "a high risk of further alienating detainees and making them ill-equipped and unprepared to return to society".

"The terrorist units ignore the responsibilities that Dutch penal institutions have toward social rehabilitation. Instead, the system can produce results that counter its goal of increasing safety and security," he said.

A spokesperson for the Dutch Ministry of Justice and Safety told broadcaster NOS that all prisons in the Netherlands, including the terrorist units, meet international standards. Reforms are being implemented, the spokesperson added. A new assessment method will allow authorities to separate extremists to ensure that they do not convert other detainees. He stressed that every prisoner is treated in a humane and safe manner.