A Royal Navy member has died following a training incident in the English Channel on Wednesday evening.
The incident involved a Merlin Mk4 helicopter which ditched during night-flying exercises with the HMS Queen Elizabeth aircraft carrier near Dorset.
A spokesperson for the Royal Navy said that there were no other fatalities or serious injuries.
The Royal Navy pledged a full investigation into the incident.
Three crew members were on board the Merlin Mk4, which ditched - a deliberate emergency landing on water - on Wednesday.
Two were rescued and taken to hospital. It is understood that they are not seriously injured.
The third crew member, whose body was recovered, has not been named.
It is also not known who on board survived and who didn't.
Another Merlin helicopter was in the air at the time of the incident.
In a post on X, Prime Minister Keir Starmer said he was "deeply saddened to hear of the tragic death of a member of the Royal Navy".
On a visit to the HMS Diamond destroyer in Portsmouth, Defence Secretary Jonathan Healey told the BBC: "Today is a day to mourn the loss of a valued navy personnel and think about his family, friends and colleagues.
"For everyone connected with the armed forces this is news that people dread."
First Sea Lord Ben Key said he was "intensely saddened" by the incident.
It is understood that HMS Queen Elizabeth, which was also involved in the night-flying exercise, is still working at sea.