Greenland and Denmark will hold high-stakes talks on Wednesday in Washington over US ambitions to annex the Arctic island, vowing to “go in together and leave together”.

Amid sustained pressure from Washington, Danish prime minister Mette Frederiksen conceded on Tuesday that “the hardest part is still ahead of us”.

US president Donald Trump insists his country will take over Greenland “the easy way or the hard way”, citing security concerns and mineral interests, and his administration has not ruled out the use of force to do so.

Greenland’s prime minister Jens-Frederik Nielsen insisted on Tuesday his island, a largely autonomous part of the three-country Kingdom of Denmark, “cannot be bought” and its future will be decided only by its people.

“If we have to choose between the US and Denmark here and now, then we choose Denmark,” he said. “We choose Nato, the Kingdom of Denmark and the EU … that is the message we will be taking with us to the US tomorrow.”

‘Make America Go Away’: The red hat that’s all the rage in GreenlandOpens in new window ]

Danish and Greenland foreign ministers Lars Løkke Rasmussen and Vivian Motzfeldt will hold talks with their US counterpart Marco Rubio, attended also by US vice-president JD Vance.

In recent days Ms Motzfeldt has floated the idea of direct talks with Washington and without Copenhagen, a position not covered by Greenland’s self-governance treaty with Denmark.

Asked what Greenland would do if asked to talk to the US alone, Mr Nielsen said: “We stand together in this situation. We go into the room together and we talk to the Americans together and we leave together.”

Ms Frederiksen has warned in recent days that any US attempts to take Greenland from Denmark, a Nato ally, would collapse the military alliance.

On Tuesday she again dismissed US claims that Denmark is not doing enough on Greenland’s security, citing multibillion investments, but said Copenhagen was willing and able to do even more.

“We have shown that for many years and we are willing to invest more in whatever it takes,” she said, adding that the US could also do more.

“The United States has an agreement with Denmark where they can post more soldiers on the island upon request but [numbers] have dropped tremendously in the last decades with only one [military] base left.”

Derek Scally: Unease in Greenland as Trump revives his Arctic ambitionOpens in new window ]

EU member states have backed Denmark and Greenland in the stand-off with Washington, while European Nato members have floated the idea of a new Arctic patrol in the region.

German chancellor Friedrich Merz said his government was in “extensive discussions” with Denmark on this issue.

“We share the American concerns that this part of Denmark needs better protection,” he said. “I hope that we can reach a mutually agreeable solution within Nato.”

Officials in Greenland and Denmark say there is no evidence to back Mr Trump’s claims that Russia and China are a security threat.

On Friday Mr Trump vowed to “do something on Greenland, whether they like it or not, because if we don’t do it, Russia or China will take over Greenland, and we’re not going to have Russia or China as a neighbour”.

On Friday and Saturday, a cross-party US senate delegation will visit Greenland, responding to an invitation by Greenlandic MP Aaja Chemnitz.

Meanwhile, Mr Trump’s special envoy to Greenland, Jeff Landry, a Republican senator for Louisiana, has promised to visit Greenland soon.

Last month Mr Landry said the Trump administration was not going to “go in there trying to conquer anybody” or “take over anybody’s country”.

This week Mr Landry said he had been invited to attend Greenland’s national dog racing championships. That has prompted an internal investigation at the tournament’s organiser to find out who – if anyone – extended the invitation.