A soldier has been shot dead during a live firing exercise at a military training area in Northumberland, police said.
The male soldier, serving with the Royal Regiment of Scotland, died in Otterburn at about 23:15 BST on Monday.
Northumbria Police said the soldier sustained a “serious head wound” and was pronounced dead at the scene. No-one has been arrested.
The soldier has not yet been identified by the Ministry of Defence.
An MOD spokesman said the Defence Safety Authority was investigating. It said there were no details on whether any other personnel were involved.
Armed Forces Minister Mike Penning said his thoughts were with the soldier’s family, friends and colleagues “at this difficult time”.
At the scene: Mark Denten, North East news correspondent
At the entrance to Otterburn Camp just off the main A68 road, a red flag flutters in the warm breeze.
It’s a sign live firing is likely – because beyond it is one of the largest military bases in Britain.
In 60,000 acres of wild but beautiful Northumberland countryside, 1,600 soldiers are training right now. Every year 30,000 pass through here.
Today there’s nothing to indicate what happened here last night – I’m passed by two army Land Rovers who politely signal their thanks.
A helpful but firm guard at the base security barrier says he cannot confirm any information.
Mr Penning added: “The safety of our personnel is our absolute priority and while deaths in training don’t happen often, any death is a tragedy.
“As well as a police investigation, MOD accident investigators are looking into the circumstances surrounding this tragic incident.”
A police cordon is in place at the training area and the soldier’s next-of-kin have been informed, police say. The force said no arrests had been made.
Deaths during live fire exercises
By Jonathan Beale, defence correspondent
Between January 2000 and 20 February 2016, 135 UK armed forces personnel died while on training or exercise.
Eleven of those 135 deaths occurred during a live fire exercise.
The police are now investigating and they need to work out if anything is suspicious, if any crime has been committed. I think it’s probably unlikely.
These are live fire exercises, in other words real ammunition is being used. I understand it was just rifles at the time; it wasn’t mortars or artillery involved in this particular exercise.
There are strict controls in place, and there are marshals involved to supervise the safety.
Also, there are strict lines of fire where the live fire goes, to ensure that those taking part are not hurt. But clearly something went wrong in this incident.
This wasn’t basic training, this was someone who was already trained and was going through a refresher. If the police don’t find anything suspicious then the army will have their own investigation into what went wrong.
Otterburn Training Area, set up by former prime minister Sir Winston Churchill, is the second largest live firing range in the country and has been used for military training since 1911.
The Royal Regiment of Scotland marked the 10th anniversary of its creation with a parade in Edinburgh in April.
The creation of the regiment in 2006 was controversial as it meant that names of famous regiments, such as the Royal Scots and the King’s Own Scottish Borderers, would disappear.