The US president says control over the island is a matter of "national security" for Washington

Denmark's Prime Minister Mette Frederiksen has urged Washington to stop threatening a "historically close ally," after President Donald Trump suggested that Copenhagen cannot properly manage and protect the island from perceived Russian and Chinese threats.

"We do need Greenland, absolutely. We need it for defense," Trump told The Atlantic on Sunday, noting that it was up to others to decide the wider implications of the US military action in Venezuela.

In response, Frederiksen said "the US has no right to annex any of the three countries in the Danish Kingdom."

"I would therefore strongly urge the US to stop the threats against a historically close ally and against another country and another people who have very clearly said that they are not for sale," she told the media.

Trump first proposed buying Greenland, an autonomous territory within Denmark, in 2019, a plan swiftly rejected by Copenhagen and Greenland's authorities. Since returning to office last year, he has revived the idea, even hinting at the possible use of force.

Denmark has responded by strengthening Arctic defenses and expanding military and civilian monitoring, viewing the pressure as a direct threat to its sovereignty.

"You know what Denmark did basically, to boost up security in Greenland? They added one more dog sled," Trump told journalists aboard Air Force One later in the day, claiming that the island is "surrounded by Russian and Chinese ships" and that Copenhagen can't handle the "threat."

"We need Greenland from the standpoint of national security. And the European Union needs us to have it, and they know it," he stated, adding, "let's talk about Greenland in 20 days."

Tensions over Greenland have continued to rise in recent weeks. In December, Trump appointed Louisiana Governor Jeff Landry, who has openly backed incorporating Greenland into the US, as a special envoy to the territory, prompting Copenhagen to summon the US ambassador for an explanation.

After the US launched a controversial military operation in Venezuela on Sunday, a former Trump administration official, Katie Miller, suggested in a cryptic social media post that Washington will "soon" take over Greenland.