Hillwalkers relying on smartphone apps to navigate Scottish mountains are putting their lives at risk, police have said.
Over the past four nights, Cairngorm mountain rescue team and the joint Grampian Police/Braemar mountain rescue team have responded to four separate incidents involving 18 people within the Cairngorms.
The searches were supported by the Search and Rescue Dog Association, Aberdeen mountain rescue and a Royal Navy search and rescue helicopter from Prestwick.
All people were traced safe and well but police said that the groups involved all appeared to have been trying to navigate using smartphone-type technology.
Mountain rescue teams and police said they were disappointed that walkers appeared to be relying completely on navigation technology, which rescuers would consider unsuitable for the terrain the groups were crossing.
Grampian Police urged hillwalkers to ensure they have have the correct level of skill and equipment, particularly with regards to navigation.
Chief inspector Andrew Todd, co-ordinator of mountain rescue in Grampian, said: "I have been involved in mountain rescue for nearly 20 years and, whilst technology can and does play an important part in raising the alarm or assisting navigation, it appears we may be about to witness a marked increase in the complete reliance of smartphone apps to navigate some of the UK's highest mountains.
"What is particularly concerning is that the individuals who are relying on this apparently inappropriate technology often do not possess even rudimentary mountain navigation skills.
"This is putting their lives at risk, and whilst Scotland's mountains are there for all to enjoy, there is a personal responsibility on those who venture into the mountains to do so only when properly equipped and skilled."
Simon Steer, deputy leader of the Cairngorm mountain rescue team, said: "Last night alone, we were involved in two separate incidents, involving a total of sixteen people, who had relied on smartphone apps to navigate on the high tops, were very poorly equipped for the conditions and become lost in the Cairngorms.
"Whilst these advances in technology are a great addition to the range of navigational aids, they do not remove the two key requirements to travel safely in the mountains which are the ability to navigate using traditional map and compass, even when supported by other technologies, and the need to go to the hills properly equipped for Scottish mountain weather.
"It's great that more people are venturing into the hills, but we need to be very aware of the limitations of new technologies and avoid relying solely on them.
"Apps don't give you a risk free passport to the mountains - if nothing else, the batteries don't last indefinitely."
In the latest incident last night, a group of 16 walkers were led to safety after they got lost in the Cairngorm mountains.
They raised the alarm at 7pm by mobile phone after they became immersed in fog. The walkers were found on Ben Macdui at 10.45pm and were led to safety.