A prisoner has died in custody at Magilligan Prison in County Londonderry, the Northern Ireland Prison Service has confirmed.
The 27-year-old died on Friday morning, it said in a statement. His next of kin have been informed.
The PSNI, Coroner and Prisoner Ombudsman have launched investigations into the death.
Prison Service head Ronnie Armour said his thoughts and those of the service were with the prisoner's family.