Before his inauguration, Donald Trump had a 45-minute phone conversation with Danish Prime Minister Mette Frederiksen regarding the possibility of purchasing Greenland. The conversation was described as tense and complicated,

President Trump reportedly held a “fiery” call with Denmark’s Prime Minister Mette Frederiksen over the president’s insistence that U.S. control of Greenland is necessary for American national

The Financial Times reports that Trump threatened Denmark's prime minister in a "horrendous" 45-minute phone call. From the reportage, you get the impression that Mette Frederiksen hadn't considered the possibility Trump was serious about Greenland and wasn't briefed on how to address the subject.