By Billy Stockwell, Betul Tuncer, CNN

(CNN) — Denmark’s foreign minister on Monday said he was “deeply upset” by US President Donald Trump’s appointment of a special envoy to Greenland who openly declared that he wished to see the island become part of the United States.

Trump announced the appointment of Jeff Landry, the Governor of Louisiana, as ‌special envoy to Greenland on Monday in a post on Truth Social. “Jeff understands how essential Greenland is to our national security, and will strongly advance our country’s interests for the safety, security, and survival of our allies, and indeed, the World,” Trump posted on his social media platform.

“I am deeply upset by this appointment of a special envoy. And I ‌am particularly upset by his statements, which we find completely unacceptable,” Lars Løkke Rasmussen told Denmark’s national broadcaster TV 2, according to Reuters news agency.

Rasmussen said he would summon the US ambassador to Denmark in response to the Trump administration’s move, Reuters reported.

Trump defended his decision to pick Landry, telling reporters on Monday evening that the US needs Greenland “for national security” and that Landry had approached him about the assignment.

“Louisiana, the Louisiana Purchase. He said I’m governor of Louisiana, and he said I would love … I didn’t call him, he called me. He’s very proactive,” Trump told reporters at Mar-a-Lago.

“We need Greenland for national security, not for minerals. We have so many sites for minerals and oil and everything,” Trump said, trying to make the case for annexing Greenland, despite its status as a self-governing territory of Denmark. “If you take a look at Greenland, you look up and down the coast, you have Russian and Chinese ships all over the place. We need it for national security. We have to have it,” he added.

During his Monday remarks, Trump went on to claim that Denmark has “spent no money” on Greenland and has “no military protection.”

While thanking Trump for his appointment, Landry said it was an “honor to serve you in this volunteer position to make Greenland a part of the US.” He also said that “this in no way affects” his position as Louisiana governor.

Trump has repeatedly stated that he wants to annexe Greenland – a huge, resource-rich island in the Atlantic and self-governing territory of Denmark – claiming that this is needed for American security purposes.

Both Greenland and Denmark, a NATO ally of the US, are staunchly opposed to the idea.

Danish Prime Minister Mette Frederiksen and Greenland’s Prime Minister Jens-Frederik Nielsen reiterated their opposition Monday to US plans to take over Greenland, stating “you cannot annex another country, not even with an argument about international security,” according to Reuters.

“Greenland belongs to the Greenlanders and the US shall not take over Greenland,” they said in a joint statement.

Nielsen said earlier Monday that Trump’s announcement “may sound big, but it does not change anything for us. We decide our own future,” Reuters reported.

Vice President JD Vance made a controversial visit to the island in March, repeatedly claiming that it was vulnerable and that the US had “no other option” than to ramp up its presence there.

In August, the US envoy to Denmark was summoned by the Danish foreign ministry after the country’s public broadcaster reported that several American men had attempted to conduct “influence operations” in Greenland.

Rasmussen said earlier that the new appointment “confirms the continued American interest in Greenland,” Reuters reported. “However, we insist that everyone – including the US – must show respect for the territorial integrity of the Kingdom of Denmark.”

Meanwhile, European Union spokesperson Anouar El Anouni said that “preserving the ⁠territorial integrity of the Kingdom of Denmark, its ‍sovereignty ‍and the inviability of its borders is essential for the European Union.”