Emergency services were called to rescue around 40 army cadets who got into difficulty in Northern Ireland's Mourne Mountains.
Coastguard, ambulance and helicopter crews were sent to the Annalong Valley.
On Facebook, the coastguard said as many as 70 people were "in difficulty after being caught out in inclement weather."
The Northern Ireland Ambulance said 16 members of the group were suffering from hypothermia.
They are all being helped off the mountains by members of the emergency services.
The mountain rescue team said: "At the minute there is no one in difficulty because they are all being looked after.
"At the minute it is nothing out of the ordinary."
The rescue team added: "Everything is under control and within normal team procedure.
"At present the members of the group are being guided by the team to nearby road access.
"NIAS [Northern Ireland Ambulance Service] are in attendance to provide any medical support required."
The cadets, aged 12 to 17, were from Middlesbrough and were at their annual camp in Northern Ireland, carrying out adventure training and cultural visits.
According to the Ministry of Defence, 43 young people and 10 leaders were in the group.
A Mourne Mountain Rescue spokesman said: "Weather has caught them out. At the minute it is not a major incident."
Colin McGrath, an SDLP MLA, tweeted: "Major emergency incident in the Mournes with helicopter, coastguard, medical and ambulance responding.
"Please God all will be ok."
Newcastle, Bangor and Kilkeel Coastguard Rescue Teams, and the UK Coastguard search and rescue helicopters based at Caernarfon and Prestwick, were on scene.
Also attending were the Irish Coastguard Rescue 116 helicopter, Mourne Mountain Rescue Team, Police Service of Northern Ireland (PSNI) and ambulance service.
An MoD spokesman said: "We are exceptionally grateful for their assistance."
