NATO began its biennial drills in the Arctic on Monday, this time placing more emphasis on the role of civilians in supporting the military, at a time of high tension over U.S. President Trump's push to take over Greenland from fellow NATO member Denmark.

The drills, named Cold Response, focus on defending the alliance in the European Arctic, where NATO-members Norway and Finland share a border with Russia, and will run March 9-19 this time.

The exercise has now become part of Arctic Sentry, the NATO mission to strengthen its presence in the polar region that was launched to defuse tensions with Trump over Greenland.

Trump insists the U.S. needs Greenland to fend off threats from Russian and Chinese interests in the Arctic, and that Denmark cannot ensure its security. The governments of both Denmark and Greenland say the island is not for sale.

This year, some 25,000 troops from some 14 nations - including the U.S. and Denmark - will take part in Cold Response, mostly across northern Norway and Finland.

The U.S. is expected to have some 4,000 troops present.

Ahead of the exercise, the U.S. military withdrew one squadron of F-35 fighter jets from the exercise. It declined to say whether the war in the Middle East played a role in the decision.

"The U.S. military is a globally deployed force and it is not abnormal for forces to be dynamically re-tasked or reallocated for a host of reasons," a spokesperson for the U.S. Marine Corps Forces Europe told Reuters.

FOCUS ON CIVILIAN READINESS

Norway has declared 2026 the year of "total defence", which puts emphasis on boosting the readiness of civilians, businesses and public institutions to cope with war and other catastrophes, the latest move by a Nordic nation to boost civilian preparedness.

"We want our military to do its job of defending the country. To do that, we are completely reliant on most aspects of society functioning as normal," Major-General Lars Lervik, head of the Norwegian Army, told Reuters.

"This is also an opportunity to rehearse specifically where civilians can give direct support to the military effort, for instance with the health service treating a higher number of injured soldiers, Norwegian or from allied forces, than usual."

On Thursday, the military will run a scenario testing the ability of hospitals in northern Norway to treat a high number of casualties being transported from an imaginary frontline in Finland.

-Reporting by Gwladys Fouche in Oslo; Editing by Kevin Buckland/Reuters