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 look ahead at the forecast for the Border region.
An undercover Trading Standards tobacco and alcohol sales operation has shown that local businesses are refusing to sell to underage people.
The Jim Clark Rally is changing the format, this years event on Sunday 31st May will run on private Forestry Commission gravel roads.