Governments should ban solitary confinement for juveniles and for people with mental disabilities, a special UN envoy said.
The UN special rapporteur on torture Juan Mendez told a UN General Assembly panel that solitary confinement "is a harsh measure which is contrary to rehabilitation, the aim of the penitentiary system."
He said all countries should move to end this practice for prisoners except in extreme circumstances.
"Segregation, isolation, separation, cellular, lockdown, Supermax, the hole... whatever the name, solitary confinement should be banned by states as a punishment or extortion technique," he said.
He also said indefinite and prolonged solitary confinement in excess of 15 days should be ended, citing studies that have established that lasting mental damage is caused after a few days of isolation.
"Considering the severe mental pain or suffering solitary confinement may cause, it can amount to torture or cruel, inhuman or degrading treatment or punishment when used as a punishment, during pre-trial detention, indefinitely or for a prolonged period, for persons with mental disabilities or juveniles," he said.
Mendez said the practice should be used only in very exceptional circumstances and for as short a time as possible, adding that if it is used then "procedural safeguards must be followed."
He said these circumstances could include the protection of inmates in cases where they are gay, lesbian or bisexual or threatened by prison gangs.