Investigation after offenders get on Swansea Prison roof
An investigation is under way after three prisoners gained access to the roof of Swansea Prison.
The men climbed on to the roof at 09:50 BST on Sunday, the Prison Service said.
A spokesman said the incident would be referred to the police, adding the prisoners had been moved to a segregation unit and would be stripped of privileges.
Ministry of Justice officials denied the protest had been linked to the smoking ban.
One claimed the prisoners involved were "recovering contraband items".