Prince William and Prince Harry say they are "shocked and deeply saddened" by the death of their friend Charles Stisted in a helicopter crash in Northern Ireland.
Rescue teams work at the isolated scene
Mr Stisted, 47, was the chief executive officer of The Guards Polo Club in Windsor, Berkshire, and a close friend of their father The Prince of Wales.
He was one of three people killed when an Agusta helicopter went down at a remote spot in the Mountains of Mourne in County Down at around 4pm on Saturday.
The Times said the helicopter's owner Ian Wooldridge also died in the crash, which is being investigated by the Air Accidents Investigation Branch of the Department for Transport.
A spokesman for Clarence House told Sky News: "The Prince of Wales, The Duchess of Cornwall, Prince William and Prince Harry are all shocked and deeply saddened by this terrible tragedy."Their Royal Highnesses thoughts and prayers are with the families of those killed at this dreadful time."
It is thought the helicopter was returning to England after a shooting trip.
Prince Charles was a close friend
Emergency services were alerted when a member of the public reported seeing an aircraft in distress.After a lengthy recovery operation, police confirmed that the pilot and his two passengers were killed.
South Down MP Margaret Ritchie said: "The local community is in absolute shock, but their thoughts are with the families and friends of the victims."
She visited the rescue teams and praised their efforts, saying they faced a tough task accessing the top of Eagle Mountain where the wreckage was found.
Sinn Fein MP for Fermanagh and South Tyrone Michelle Gildernew said: "The shock of this accident has been felt by people right across Co Down and Co Fermanagh."
Democratic Unionist representative for South Down Jim Wells said the area had suffered a string of deaths in recent years.
In June last year three men were killed when their light aircraft crashed into a field near a private landing strip at Kilkeel, Co Down.
