Danes voiced shock and disbelief on Wednesday at U.S. President Donald Trump’s cancellation of a visit to Denmark after his idea to buy Greenland was rebuffed, although Prime Minister Mette Frederiksen said she believed relations would not be affected, reports Reuters.

Trump’s proposal at first elicited incredulity and humor from politicians in Denmark, a NATO ally of the United States, with former premier Lars Lokke Rasmussen saying: “It must be an April Fool’s Day joke.”

But the mood turned to bewilderment when Trump called off the Sept. 2-3 visit after Frederiksen called his idea of the United States purchasing Greenland, an autonomous Danish territory rich in natural resources, “absurd”.

“Everyone should know Greenland is not for sale,” Danish foreign minister Jensen said.

Trump, whose “America First” policies have resulted in strained relations with the EU over trade and other issues, said on Sunday a U.S. purchase of Greenland would be “a large real estate deal.”

“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 tweeted on Tuesday.