JOYCEVILLE, Ont. - A medium security prison northeast of Kingston, Ont., is in lockdown following an assault on an inmate, the second in three days.

Joyceville Institution assistant warden Lorrie Oddie says a prisoner was assaulted Monday afternoon, and taken to an outside hospital for treatment.

No staff members or other inmates at the prison near Joyceville were injured, and the Joint Forces Penitentiary Squad and the institution are investigating.

The lockdown includes an exceptional search of part of the institution, and normal activities will resume when it's safe to do so.

Another prisoner was assaulted at Joyceville on Saturday evening, and was taken to hospital for treatment.

That incident is also being investigated