Danish Foreign Minister said he would call a U.S. ambassador to resolve a report saying Washington's spy agency was told to focus on Greenland because Donald Trump threatened to take over the island.

"It's a big concern for me because we don't monitor our friends," Lars Løkke Rasmussen said in response to the report in the Wall Street Journal.

According to the newspaper, U.S. spy agencies were told to focus their efforts on the independence movement in semi-autonomous countries and the U.S. goal to extract mineral resources there.

National Intelligence Agency Director Tulsi Gabbard accused the magazine of trying to "destroy President Trump" by politicizing and leaking confidential information.

While not denying the report, she accused the newspaper of "violating the law and undermining the security and democracy of our country."

Rasmussen, who is attending the EU ministerial meeting in Warsaw, said the report is "somewhat disturbing".

"We will have a discussion at the Department of Foreign Affairs at the acting ambassador to see if we can confirm this information," Rasmussen said.

"It doesn't seem to be strongly rejected by those who speak out loud. It's a concern for me."

The Danish Security and Intelligence Service (PET) declined to comment on the article, but told Danish media that it "naturally" noticed the U.S. interest in Greenland.

The agency said that based on international interest in Greenland, the threat of spy to IT and Denmark increased.

President Trump has vowed to take control of Greenland several times, and recently told NBC News on Sunday that he did not rule out the use of military force to seize the Arctic Island.

"I'm not saying I'm going to do this, but I don't rule out anything," he said. "We need Greenland very much. Greenland is a very small number of people, we will take care of, we will cherish them, all of that. But we need this for international security."

Trump told U.S. lawmakers in a March Congress speech, “One way or another, we will get it.”

Danish officials also condemned Vice President JD Vance's visit to Greenland in March.

Danish Prime Minister Mette Frederiksen said visiting U.S. military bases is “completely unacceptable for Greenland, Greenland politicians and Greenland population.”

Former President Joe Biden spoke to BBC News in his first interview since leaving the office in January, condemning Trump's call for the United States to retake the Panama Canal to acquire Greenland and make Canada the 51st state.

Biden told BBC's Nick Robinson: "What the hell is it?

“We are about freedom, democracy, opportunity, not about confiscation.”

Greenland is the largest island in the world and has been controlled by Denmark for about 300 years. The island manages its own internal affairs, but diplomatic and defence policy decisions were made in Copenhagen.

The United States has long had a security interest on the island. It has had military bases there since World War II, and Trump may also be interested in rare earth minerals that can be mined.

Polls show that the vast majority of Greenlanders want independence from Denmark but do not want to be part of the United States.