Nato forces gather for Exercise Joint Warrior in Scotland
One of Europe's largest Nato exercises begins in Scotland this weekend.
Exercise Joint Warrior is held twice a year - in April and October - for thousands of army, navy and air force personnel.
The training will see increased military activity at Faslane on the Clyde, RAF Lossiemouth in Moray and ranges at Cape Wrath in Sutherland.
The exercise runs until 23 April and will involve submarines, surface ships and aircraft including RAF Typhoons.
Warships and aircraft have already started arriving in Scotland ahead of the start of the training.
This year's second staging of Joint Warrior, which will also take place in Scotland, will include what the Royal Navy has described as its first "robot wars".
Unmanned Warrior 2016 will involve drones, including unmanned aerial vehicles and machines that can operate underwater.
Companies that manufacture the weapons and Nato member countries have been invited by the Royal Navy to take part.