The largest military exercise in the UK this year has started in south west Scotland and northern England.
The exercise is taking place in Scotland and England
Exercise Griffin Focus is one of the most important exercises in the Army's training year and runs to 24 June.
It involves more than 5,000 troops sited mainly around Carlisle, Dumfries, Dalbeattie, the Galloway Forest, West Freugh, Luce Bay and Stranraer.
Military vehicles will also be involved and the Army said it will attempt to keep disturbance to a minimum.
The exercise aims to bring regular and territorial troops together for a concentrated period of training.
It will provide units with specialist roles an opportunity to work together.
Exercise Griffin Focus is set against the fictional background of a country recovering from the effects of an invasion.
Units will carry out tasks working under a fictional mandate to provide humanitarian assistance.
Their tasks will include building and running a large field hospital, setting up refuelling areas, communication facilities, headquarters and logistics bases.
The troops will also be practising convoy drills, search and rescue tasks, amphibious operations and beach landings.
The Army will be joined by the Royal Navy, RAF and foreign naval forces during the operation.
Deployment of troops will take place at locations where permission has been obtained and been cleared with the landowner or tenant farmer concerned.
All personnel involved in the exercise have been briefed on the requirement to avoid disturbance to traffic, property and livestock.