A second soldier has died following an incident at a military firing range in Pembrokeshire.
Both victims were from the Royal Tank Regiment and were injured at Castlemartin on Wednesday afternoon, Defence Minister Tobias Ellwood said.
Two people are still being treated for their injuries.
Mr Ellwood said: "It is with great sorrow I can confirm the death of a second soldier from the Royal Tank Regiment following yesterday's incident at Castlemartin Ranges."
The range is used for tanks and armoured units to carry out direct-fire live gunnery exercises.
Paramedics were called to the scene shortly after 3.30pm on Wednesday, taking two men to Morriston Hospital, Swansea, one to Heath Hospital in Cardiff and air-lifting a fourth to a Birmingham hospital.
The two other soldiers hurt were said to be in a critical condition.
A 48-hour worldwide ban was subsequently imposed on the ammunition which had been fired during the fatal training exercising.
A statement from the Royal Tank Regiment - the oldest tank unit in the world, according to its website - said its investigations were continuing.
It said: "Our thoughts are with the friends and families of all those involved."
The regiment was formed at around the time of the First World War and had 25 battalions fighting across the globe during the Second World War.
The regiment, based in Tidworth, Wiltshire, consists of three squadrons - Ajax, Badger and Cyclops - each equipped with 18 Challenger 2 battle tanks, the unit's Ministry of Defence website says.
On June 7, the regiment posted on its Facebook page saying Badger squadron had arrived in Castlemartin for its annual firing period.
"Stay tuned for more photos and videos of the awesome firepower of the Challenger 2," the post said.
On June 11, an update showed a video of a tank firing on the range.
It was captioned: "FIRING! Here a crew from BADGER take on a tank target in Castlemartin. FEAR NAUGHT."
The deadly incident came five years after a 21-year-old soldier died when he was shot in the head while relaxing at a safe location outside Castlemartin.
A 2013 inquest into the death of Mike Maguire heard he was hit in the temple by a single bullet after live machine gun fire was wrongly directed inland towards the safe haven.
The inquest jury ruled Ranger Maguire, a member of the 1st Battalion, The Royal Irish Regiment, was unlawfully killed.