The Irish Prison Service and the Gardai say they're investigating the death of an inmate at Mountjoy Prison.

A man in his 30s died in the early hours of this morning, after falling ill in his cell.

The man was found unconscious and taken to the Mater Hospital but died a short time later.

A post-mortem has been concluded on body of a man found dead in his cell in Mountjoy Prison. No official cause of death has yet been announced.