The UK and Germany are drawing up plans aimed at preventing US President Donald Trump from seizing Greenland, Bloomberg and The Telegraph reported over the weekend.

Trump has long argued that the US should control the Danish self-governing island, citing its strategic position and the need to deter the influence of Russia and China in the Arctic. His stance has put him at loggerheads with several European NATO members, who have rallied behind Denmark.

Berlin and London are seeking to ramp up NATO presence in the region to undercut Trump’s security argument. A German proposal involves a joint NATO mission dubbed ‘Arctic Sentry,’ Bloomberg reported, citing officials familiar with the discussions. German Foreign Minister Johann Wadephul is expected to discuss the issue with US Secretary of State Marco Rubio this week.

“I want to discuss on my trip how we can best bear this responsibility in NATO,” Germany’s top diplomat told journalists on Sunday.

According to The Telegraph, British officials have also met with their counterparts from Germany and France in recent days to draw up plans for a possible NATO mission in Greenland. The proposals were discussed at a NATO meeting on Thursday, the paper said.

Options suggested by London include military exercises, intelligence sharing, targeted defense spending, and a full-scale troop deployment to Greenland, The Telegraph added, noting that the planning remains at an early stage.

Trump stated on Saturday that the US would acquire Greenland “whether they like it or not,” warning that he could accomplish this “the hard way.” While media outlets have said the US was considering purchasing the island and offering its residents financial incentives, the White House has declined to definitively rule out the use of military force.

On Sunday, the Daily Mail reported that Trump ordered senior commanders to draw up plans for a potential invasion of Greenland. Several European officials, including Danish Prime Minister Mette Frederiksen, have warned that a military attack on a fellow NATO member would render the alliance obsolete.