COPENHAGEN, Denmark — Escalating an international spat, President Donald Trump said Wednesday he scrapped his trip to Denmark because the prime minister made a “nasty” statement when she rejected his idea to buy Greenland as an absurdity.

“You don’t talk to the United States that way, at least under me,” Trump told reporters in Washington. “I thought it was not a nice statement, the way she blew me off.”

Danish Prime Minister Mette Frederiksen called the whole thing “an absurd discussion” and said she was “disappointed and surprised” that Trump had canceled his visit.

Trump said Frederiksen’s comment labeling his idea as absurd “was nasty. I thought it was an inappropriate statement. All she had to say was say, ‘No, we wouldn’t be interested.’”

Greenland is a semi-autonomous territory of the U.S. ally, and Frederiksen said the U.S. remains one of Denmark’s close allies.

The political brouhaha over the world’s largest island comes from its strategic location in the Arctic. Global warming is making Greenland more accessible to potential oil and mineral resources. Russia, China, the U.S., Canada and other countries are racing to stake as strong a claim as they can to Arctic lands, hoping they will yield future riches.

Trump was scheduled to visit Denmark on Sept. 2-3 as part of a European tour. But early Wednesday, he tweeted his decision to indefinitely postpone the trip. The move stunned Danes and blindsided the Danish royal palace. Spokeswoman Lene Balleby told The Associated Press that it came as “a surprise” to the royal household, which had formally invited Trump.

“Denmark is a very special country with incredible people, but based on Prime Minister Mette Frederiksen’s comments, that she would have no interest in discussing the purchase of Greenland, I will be postponing our meeting scheduled in two weeks for another time,” Trump said.

The vast island of Greenland sits between the Atlantic and Arctic oceans, has a population of 56,000 and has 80% of its land mass covered by a 1.7 million-square-kilometer (660,000 square-mile) ice sheet.

For all of Greenland’s appeal, scientists consider it the canary in the coal mine for climate change and say its massive ice sheet has seen one of its biggest melts on record this summer, contributing to a global rise in sea levels.

Frederiksen said she is standing behind the government of Greenland.

“A discussion about a potential sale of Greenland has been put forward. It has been rejected by Greenland Premier Kim Kielsen and I fully stand behind that rejection,” she told reporters in Copenhagen.

Frederiksen, who took office two months ago in a minority Social Democratic government, went on to say that diplomatic relations between Copenhagen and Washington “are not in any crisis in my opinion” despite Trump’s canceled plans.