More than 3,000 troops are taking part in "Operation Joint Warrior" in and around Galloway Forest in Dumfriesshire.
A group of British and French paratroopers are also carrying out a parachute drop near to the Braid Fell area.
More top news
A new look for our political programme from Westminster - Paul Brand and guests consider Theresa May's vision for Brexit.
Calm but cloudy - but when will we see some sunshine?
Students and staff from the University of Cumbria have been forced to cancel a zoology research trip to Gambia, due to political unrest.