President Donald Trump has made it abundantly clear that he is highly interested in acquiring the Arctic island of Greenland for the United States, but has unsurprisingly encountered substantial resistance to the idea from the leaders of Greenland and Denmark, the European nation that ostensibly holds sovereign rights over the territory.

Reports indicate that Trump recently had a contentious phone call with Danish Prime Minister Mette Frederiksen about Greenland, during which he was told in no uncertain terms that his plan to gain control of the island territory would be fiercely opposed, according to the Daily Mail.

Though some might assume that Denmark's and Greenland's unmitigated rejection of Trump's advances would be the end of the story or that a possible deal is never happening, that would likely be an unsafe bet as Trump has displayed a certain persistence about Greenland and will likely keep searching for a way to bring the strategically important territory under U.S. sway.

Contentious phone call with Danish PM

The Financial Times reported this week on an alleged "fiery" phone call that happened a few days before President Trump took office between him and Danish PM Frederiksen that was said to have lasted around 45 minutes and to have "gone very badly."

Unnamed senior European officials who claimed they'd been briefed on the call said that Trump had been insistent and serious about the U.S. acquiring Greenland and had become "aggressive and confrontational" when told by Frederiksen that a deal for the Arctic territory was not happening.

One source described the conversation as "horrendous" while another told the outlet of Trump, "He was very firm. It was a cold shower. Before, it was hard to take it seriously. But I do think it is serious, and potentially very dangerous."

"The intent was very clear. They want it. The Danes are now in crisis mode," one anonymous source said while still another revealed, "The Danes are utterly freaked out by this." A former Danish official claimed, "It was a very tough conversation. He threatened specific measures against Denmark such as targeted tariffs."

That may not be precisely how the conversation went down, however, as a spokesperson for PM Frederiksen's office told FT that they did not "recognize the interpretation of the conversation given by anonymous sources."

Trump remains confident a deal can be made

The BBC reported that President Trump, who first floated the idea of acquiring Greenland during his first term in 2019 but only recently raised the subject again shortly before taking office again, seemed to express confidence on Saturday that a deal for the Arctic territory was still possible to achieve.

Speaking to reporters onboard Air Force One, Trump said of Greenland, "I think we're going to have it," and claimed of its estimate 57,000 residents, "I think the people want to be with us." He further stated, "I don't really know what claim Denmark has to it, but it would be a very unfriendly act if they didn't allow that to happen because it's for the protection of the free world."

"I think Greenland we'll get because it has to do with freedom of the world," the U.S. president added. "It has nothing to do with the United States other than that we're the one that can provide the freedom. They can't."

Why does Trump want Greenland?

Some people suspect that President Trump is only interested in Greenland so that the U.S. can gain control of the Arctic island's abundant natural resources that are locked beneath its thick sheet of glacial ice, as it is estimated that there are plentiful reserves of oil and natural gas along with exceptionally valuable rare earth minerals and other important materials like iron ore and uranium, per the BBC.

Perhaps just as critical, according to CNBC, is Greenland's geostrategic location that, if under the control of the U.S., would serve as a hedge against Russian and Chinese military expansion into the Arctic Circle as well as to protect emerging northern trade routes between North America and Europe.

According to The Arctic Institution, Trump is far from the first U.S. president to openly discuss acquiring Greenland -- either economically or through military force -- and the U.S. has had a protective presence on the island since World War II.

And, while Trump could cause an international incident and anger allies by simply seizing Greenland, the more likely option would be to purchase it, though estimated costs range from hundreds of millions of dollars on the low end to as much as a trillion on the high end, if the price of all of the estimated natural resources and strategic importance are fully factored in.