Germany and France have warned Donald Trump against threatening Greenland, after the US president-elect refused to rule out using military force to seize Denmark's autonomous territory.

German Chancellor Olaf Scholz said "the principle of the inviolability of borders applies to every country... no matter whether it's a very small one or a very powerful one".

French Foreign Minister Jean-No?l Barrot said "there is obviously no question that the European Union would let other nations of the world attack its sovereign borders".

On Tuesday, Trump reiterated his desire to acquire Greenland, saying that the Arctic island was "critical" for national and economic security.

He has repeatedly expressed an interest in buying Greenland, having mooted the idea in 2019, during his first term as president.

Denmark, a long-time US ally, has made clear that Greenland is not for sale and that it belongs to its inhabitants.

Greenland's Prime Minister, Mute Egede, is pushing for independence from Denmark, but he too has made clear the territory is not for sale. He was visiting Copenhagen on Wednesday.

Chancellor Scholz said there was a "certain incomprehension" about statements coming from the incoming US administration.

"The principle of the inviolability of borders applies to every country no matter whether that's in the east or the west."

Denmark is a member of the US-led Nato alliance, as are Germany and France.

Scholz stressed that "Nato is the most important instrument for our defence and a central of the transatlantic relationship".

Speaking earlier on Wednesday, Jean-No?l Barrot told France Inter radio: "If you're asking me whether I think the United States will invade Greenland, my answer is no.

"Have we entered into an era that sees the return of the survival of the fittest? Then the answer is yes.

"So, should we allow ourselves to be intimidated and overcome with worry, clearly not. We must wake up, build up our strength," the French foreign minister added.

Germany and France are the two leading members of the EU, often described as its main driving force.

However, it is difficult to imagine how the EU might prevent any potential attack. It has no defensive capabilities of its own and most of its 27 member states are part of Nato.

Trump made the remarks at a free-wheeling news conference at his Mar-a-Lago estate in Florida, less than two weeks before he is sworn in for his second term as president on 20 January.

Asked if he would rule out using military or economic force in order to take over Greenland or the Panama Canal, Trump said: "No, I can't assure you on either of those two.

"But I can say this; we need them for economic security."

Greenland has been home to a US radar base since the Cold War and has long been strategically important for Washington.

Trump suggested the island was crucial to military efforts to track Chinese and Russian ships, which he said are "all over the place".

"I'm talking about protecting the free world," he told reporters.

Danish Prime Minister Mette Frederiksen told Danish TV on Tuesday that "Greenland belongs to the Greenlanders" and that only the local population could determine its future.

However, she stressed Denmark needed close co-operation with the US.

Greenland MP Kuno Fencker told the BBC that the population had been preparing for "some bold statements" from Trump, but that the island's "sovereignty and self-determination are non-negotiable".

Fencker, whose Siumut party is part of Greenland's governing coalition, said local authorities would welcome "constructive dialogue and mutually beneficial partnership with the United States and other nations".

He did not rule out a free association including both Denmark and the US, but said "this is a decision that Greenlandic people must take, it's not one politician's decision".

Greenland has a population of just 57,000 and wide-ranging autonomy, although its economy is largely dependent on subsidies from Copenhagen and it remains part of the kingdom of Denmark.

It also has some of the largest deposits of rare earth minerals, which are crucial in the manufacture of batteries and high-tech devices.

Danish Broadcasting Corporation senior international correspondent Steffen Kretz, who has been reporting in Greenland's capital, Nuuk, said most of the people he had spoken to were "shocked" by Trump's refusal to rule out using military force to take control of the territory.

While a majority of people in Greenland hoped for independence in the future, he said there was widespread acknowledgment that it needed a partner who could provide public services, defence and an economic foundation, as Denmark did now.

"I have yet to meet a person in Greenland who is dreaming of the island becoming a colony for another outside power like the USA."

Kretz told the BBC that while the Danish government had sought to "downplay" any confrontation with Trump, "behind the scenes I sense the awareness that this conflict has the potential to be the biggest international crisis for Denmark in modern history".

The president-elect's son, Donald Trump Jr, paid a brief visit to Greenland on Tuesday, in what he described as a "personal day trip" to talk to people.

He then posted a photo with a group of Greenlanders in a bar wearing pro-Trump caps. (BBC)

Update news