Greenland has poured scorn on Donald Trump’s reported plan to buy the island from Denmark.

“We are open for business, but we’re NOT for sale,” said Greenland’s foreign minister Ane Lone Bagger, in a note to Reuters.

Mr Trump is due to visit Copenhagen in September and the Arctic will be on the agenda during meetings with Danish prime minister Mette Frederiksen and Greenland leader Kim Kielsen.

The US president has suggested purchasing the vast Arctic territory on numerous occasions with staff after hearing about its natural resources and geopolitical importance, according to the Wall Street Journal.

The notion of purchasing the autonomous Danish territory was laughed off by some of Mr Trump’s advisers as a joke but has been taken more seriously by others in the White House, two sources familiar with the situation said on Thursday.

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But Danish politicians mocked the notion of selling Greenland, the world’s largest island.

“If he is truly contemplating this, then this is final proof that he has gone mad,” Soren Espersen, foreign affairs spokesman for the Danish People’s Party, told broadcaster DR.

“The thought of Denmark selling 50,000 citizens to the United States is completely ridiculous,” he said.

Greenland, a self-ruling part of Denmark located between the North Atlantic and Arctic oceans, is dependent on Danish economic support.

“I am sure a majority in Greenland believes it is better to have a relation to Denmark than the United States, in the long term,” Aaja Chemnitz Larsen, Danish MP from Greenland’s second-largest party Inuit Ataqatigiit (IA), told Reuters.

“My immediate thought is ‘No, thank you’,” she said.

Ms Frederiksen, Denmark’s prime minister, was not available for comment. The US embassy in Copenhagen was also not immediately available for comment.

“Oh dear lord. As someone who loves Greenland, has been there nine times to every corner and loves the people, this is a complete and total catastrophe,” former US ambassador to Denmark, Rufus Gifford, said on Twitter.

Former prime minister Lars Lokke Rasmussen tweeted: “It has to be an April Fool’s joke. Totally out of season.”

Despite being the largest island in the world, Greenland is home to little more than 55,000 people (iStock)

The prospect of US ownership also outraged residents in Nuuk, Greenland’s tiny capital on its southwest coast.

One local simply responded, “Oh please God no”, while another tweeted, “We are not something you can just buy. Keep away from our country”, adding the hashtag “#Jerk”.

Greenland is gaining attention from global super powers including China, Russia and the US due to its strategic location and its mineral resources.

In May, US secretary of state Mike Pompeo said Russia was behaving aggressively in the Arctic and China’s actions there had to be watched closely as well.

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A defence treaty between Denmark and the US dating back to 1951 gives the US military rights over the Thule Air Base in northern Greenland.

Greenland is part of Denmark with self-government over domestic affairs, while Copenhagen handles defence and foreign policy.

There has been no indication that a Greenland purchase will be on the agenda for Mr Trump’s talks with Danish officials.

Martin Lidegaard, senior lawmaker of the Danish Social Liberal Party and former foreign minister, called the idea “a grotesque proposal” which had no basis in reality.

“We are talking about real people and you can’t just sell Greenland like an old colonial power,” he told Reuters.

“But what we can take seriously is that the US stakes and interest in the Arctic is significantly on the rise, and they want a much bigger influence,” he added.

In 1917 Denmark sold off the then Danish West Indies islands for $25m to the US, which renamed them the United States Virgin Islands.

Additional reporting by Reuters