One of two servicemen who died during the selection process for the Territorial Army's section of the SAS has been named by the Ministry of Defence (MoD).
Lance Corporal Craig Roberts died during a military exercise in the Brecon Beacons on Saturday when temperatures soared to 29.5C (85.1F).
A second soldier, who has not yet been named, also lost his life, while a third remains in hospital.
In a statement, the MoD said: "It is with great sadness that the Ministry of Defence can confirm the death of L/Cpl Craig Roberts and another Army reserve soldier during a training exercise in the Brecon Beacons at the weekend.
"Our thoughts are with their families and friends at this difficult time. The families of the soldiers have requested that their privacy is respected at this difficult time."
It is not expected that the MoD will name the second soldier.
Police and the MoD are investigating the deaths of the men, who were part of a group training in Wales's rugged Brecon Beacons on Saturday.
Sources have said the men were at the start of a period of assessment in the selection process for the Territorial Army's section of the SAS, after completing a period of training and preparation.
The deaths have led to question marks over the way rigorous SAS training is carried out, amid speculation the extreme temperatures caused the men's death, but an MoD spokesman earlier said there are no plans to change "routine exercises" in light of the incident.
Members of all four of South Wales's mountain rescue teams were called out to assist when the two servicemen died. Thirty members of Central Beacons, Brecon, Western Beacons and Abergavenny-based Longtown Mountain Rescue Teams joined the operation near Pen y Fan, the highest mountain in South Wales.