UK-led Exercise Joint Warrior to be 'biggest ever'
Nato warships, aircraft and personnel have arrived in Scotland for what has been described as the biggest ever Exercise Joint Warrior.
Joint Warrior is held twice a year - in April and October - and includes several locations in Scotland and in the sea off its coast.
The US Navy said the UK-led training this April would be on the largest scale in the history of the exercise.
Fifteen countries are taking part in the training that starts on Saturday.
The exercise, which runs until 24 April, will feature anti-submarine warfare and mock attacks on warships by small boats.
More than 50 ships and 70 aircraft, some being based at RAF Lossiemouth in Moray and Prestwick Airport in Ayrshire, along with 13,000 personnel will be involved.
Several of the surface ships and submarines have been arriving at Faslane on the Clyde.
Earlier this month, the Royal Navy said jamming will be limited to a confined area in the north-west of Scotland.
It said the relevant authorities, including aviation and maritime communities, had been consulted.
The Mountaineering Council of Scotland was this week alerting walkers and climbers to the potential disruption to GPS devices they might use in addition to a map and compass.
Jamming during Joint Warrior in October 2011 was suspended after complaints from Western Isles fishermen.
The latest war games come just weeks after a fisherman claimed a submarine may have snagged itself on his trawler as it fished off the Western Isles, an area were elements of Joint Warrior's training are held.
Angus Macleod said he and his four crew were "extremely lucky" after his net was continually dragged in front of his 62ft boat.
The Royal Navy said there were no British or Nato submarines in the area at the time.
There has been speculation in recent months that Russian submarines have been operating off the Scottish coast.