The Security Service of Ukraine (SBU) refutes reports about the alleged existence of the so-called "secret prisons of the SBU" and states that evidence has already been collected about torture of around 500 Ukrainian citizens in some areas of Donetsk and Luhansk regions.

"The Security Service of Ukraine once again refutes unreliable reports about the existence of the so-called 'secret prisons of the SBU.' We emphasize that the Service operates exclusively within the framework of the current legislation. All procedural actions with detainees are conducted in accordance with the clauses of the Criminal Procedure Code, which is confirmed by the results of inspections of representatives of international organizations on the protection of human rights," the SBU said in a press release on Tuesday.

At the same time, the SBU said it had collected documentary evidence of almost 500 Ukrainian citizens - former hostages in occupied areas in Donbas - about specific facts of physical torture and psychological harassment during hostage-taking.

"We call on all human rights organizations to provide assistance to former hostages of Russian terrorist groups in preparing relevant appeals to the ECHR," the SBU said.