NAVY MAN DIES IN SUB SHOOTING.
Local civic dignitaries, including the mayor and the council leader were onboard HMS Astute, which is visiting Southampton, at the time of the incident.
The Ministry of Defence said the shooting was not terrorist-related and there was no threat to the wider public.
An MoD spokesman said: "Two Royal Navy personnel have been involved in a firearms incident at Southampton docks, where HMS Astute is alongside.
"Sadly, one has now died as a result of his injuries. The Royal Navy is now attempting to inform their families as a matter of urgency.
"A third Royal Navy serviceman has been arrested by Hampshire Constabulary and is now in custody.
"This incident was not terrorist-related and there is no threat to the wider public.
"We are co-operating fully with the police investigation and a Royal Navy service investigation will begin in due course."
Defence Secretary Dr Liam Fox said: "I am greatly saddened to hear of this tragic incident and of the death of a Royal Navy serviceman.
"It is right and proper that a full police investigation is carried out and allowed to take its course.
"My thoughts and sympathies are with those who have been affected and their families."
It is understood that the two victims were male officers and the shooting was carried out with an SA80 service rifle.
It is also understood the gunman was on sentry duty and the shooting happened during a weapons changeover between shifts.
After the shooting, it is understood the gunman was grabbed by other navy personnel, who handed him over to Ministry of Defence Police who were there as part of the civic visit.
He was then transferred to Hampshire police officers when they arrived minutes later.
Sources said the motive for the shooting was unclear but played down the possibility of post-traumatic stress disorder being a factor, pointing out that the longest HMS Astute has spent at sea is 46 days.
POLICE PROBE: A Navy crewman was shot dead and another seriously wounded on board HMS Astute in Southampton