The deaths of two soldiers and the serious injury of two others at a Ministry of Defence base in Pembrokeshire is “awful for the area and everybody involved”, the local MP has said.
The Royal Tank Regiment soldiers died after the incident at Castlemartin Range on Wednesday.
The MoD, Dyfed-Powys Police and the Health and Safety Executive are investigating.
The incident is understood to have involved ammunition.
Simon Hart, MP for Carmarthen West and South Pembrokeshire, told BBC Wales training is often as “challenging and dangerous” as active service.