The Ministry of Defence (MoD) is investigating after a number of people are believed to have been injured at a military training base in Wales.
Police were called to an incident at Castlemartin Ranges in Pembrokeshire on Wednesday afternoon - an area of land used for tank training exercises by the Royal Armoured Corps.
An MoD spokeswoman said: "We are aware of an incident at Castlemartin Ranges. This is still being investigated and therefore it would be inappropriate to comment further."
A firing notice on the Government's website suggested live firing was expected on the range from Monday to Friday and night firing was due to take place on Tuesday and Thursday.
Castlemartin is the only UK Army range available for armoured units for direct-fire live gunnery exercises.
A spokeswoman for Dyfed-Powys Police said: "Dyfed-Powys Police were called to an incident at MoD Royal Armoured Corps range in Castlemartin range at 3.30pm (Wednesday).
"This is being investigated and a further update will be provided when appropriate."
The incident comes five years after a 21-year-old soldier died at Castlemartin when he was shot in the head while relaxing at a safe location just outside the training range.
A 2013 inquest into the death of Michael "Mike" Maguire heard he was hit in the temple by a single machine gun bullet fired by a fellow soldier during a training exercise.
The inquest jury ruled Ranger Maguire, who was a member of the 1st Battalion, The Royal Irish Regiment, had been unlawfully killed.