The UK is leading Europe's biggest war game, involving 15 countries, thousands of military personnel and several warships and fighter jets this weekend.
The biannual Joint Warrior exercise is taking place off the Scottish coast at a time where relations with Russia are strained and is due to continue until 24 April. Despite being held twice a year, the scale of the current war games surpasses previous ones.
The military drills will start today (11 April) and will feature 55 warships, 70 aircrafts and 13,000 soldiers, airmen and sailors and include submarine warfare and live firing from the land, sea and air. The UK-led training will include practice amphibious landings, mine clearing and mock attacks on warships by small boats.
Countries participating in the exercise that are NATO member states include the UK, US, Canada, Belgium, Denmark, France, Germany, Norway, Poland, Portugal, Spain, Turkey and the Netherlands. They are joined by non-NATO states Finland and Sweden.
"There will be significant naval and aerial activity off the West and East coast of Scotland, including amphibious landings on the West coast," the Ministry of Defence said in a statement.
"Elsewhere there will be aerial and ground activity including airborne landings around Salisbury Plain in England and several other Defence Estate areas in Scotland, Northern England, South Wales and Central England.
"The NATO exercise is designed to improve joint operations between the participating countries Armed Forces."
Submarine gets netted
The latest war game comes just weeks after a Scottish fisherman claimed that a submarine may have snagged itself on his 62ft trawler as he fished off the Western Isles.
Speculation has been rife in recent months that Russian submarines have been operating off Scotland's coast.
Meanwhile, Nordic countries have tightened their military cooperation in the face of perceived Russian aggression.
In a joint declaration published by the Norwegian daily Aftenposten, defence ministers from Norway, Sweden, Finland and Denmark as well as Iceland's foreign minister said they "must be prepared to face possible crises or incidents" and labelled Russia as "the biggest challenge to European security".