In the exercise scenario US and 12 European countries come to rescue.

This year, the bi-annual exercise, known as Cold Response, has taken on an added significance for some of the roughly 3,000 U.S. Marines taking part in it because of Russia’s invasion of Ukraine.

Corporal Sean Galigan, a 21-year Marine from New Jersey who is focusing on refueling aircraft during the exercise, said the invasion was in the back of his mind, even though the exercise had been planned months before Russia started building up forces near Ukraine.

“It’s always something that could happen, but now since we’re here, if something did happen, we would be ready to go,” Galigan said.

Relations between Norway and Russia, which share an Arctic border, gradually improved in the post-Cold War era before suffering a setback when Moscow annexed Crimea in 2014.

That triggered tensions in the north on both sides of the border and more frequent military maneuvers.

Even before the invasion, which Russian dictator Vladimir Putin says is a “special military operation,” Moscow accused NATO of destabilizing European security with large-scale military drills and by building up its military on the alliance’s eastern flank.

The invasion of Ukraine, which has destroyed hundreds of buildings and killed scores of civilians, has increased unease in the region.

“It feels a little more real,” a C-130 Marine Pilot said he as he flew from Bardufoss to near Evenes in Norway.

The enemy in the exercise is fictional but the parallels to what a future conflict in the region could look like are unmistakable.