Pompeo praises 'ally' Denmark and calls for more cooperation in Arctic after Trump row

US Secretary of State Mike Pompeo spoke with Denmark's foreign minister on Wednesday and praised U.S.-Danish security cooperation, a day after President Donald Trump abruptly canceled a visit to the Nordic country because it rebuffed his idea of buying Greenland.

"Secretary Pompeo spoke by phone today with Danish Foreign Minister Jeppe Kofod regarding the postponement of President Trump’s travel to Denmark," State Department spokeswoman Morgan Ortagus said in statement.

"The secretary expressed appreciation for Denmark’s cooperation as one of the United States’ allies and Denmark’s contributions to address shared global security priorities," she said. "The secretary and Foreign Minister Kofod also discussed strengthening cooperation with the Kingdom of Denmark – including Greenland – in the Arctic."

On Wednesday Mr Trump declared Danish Prime Minister Mette Frederiksen's dismissal of his idea to buy Greenland "nasty" and an affront to the United States on Wednesday, a day after shocking Danes by canceling a Copenhagen visit over the rebuff.

Danes voiced disbelief at Trump's decision to forgo the trip, although Frederiksen said she believed relations with the United States, a NATO ally, would not be affected.

Trump, who built his career as a businessman dealing in real estate, had mused openly in recent days about a US purchase of Greenland, an autonomous Danish territory rich in natural resources, raising eyebrows in Europe and in the United States.

Former Danish Prime Minister Lars Lokke Rasmussen called it "an April Fool's Day joke" and Frederiksen called the idea "absurd."

The latter comment set off Trump, who often becomes riled up by criticism, real or perceived. He announced the cancellation of his planned Sept 2-3 trip to Denmark in a tweet late on Tuesday.

"I thought that the prime minister's statement ... was nasty. I thought it was an inappropriate statement. All she had to do is say: 'No, we wouldn’t be interested,'" Trump told reporters at the White House on Wednesday. "She's not talking to me. She's talking to the United States of America. You don’t talk to the United States that way, at least under me."

Frederiksen, a centre-left Social Democrat, said she learned of Trump's decision "with regret and surprise", given Denmark's strong relations with Washington, but she repeated her opposition to any Greenland transaction.

She stressed that Greenland's premier, Kim Kielsen, had ruled out selling off the territory and "I obviously agree with him."

But Frederiksen said the United States remained one of Denmark's closest allies. "I don't think the cancelling of this state visit should affect any decisions we make whether it is on commercial cooperation or foreign and security policies."

Trump's decision elicited condemnation, outrage and mockery alike among Danish opposition leaders and the public.