Iceland summoned the US ambassador on Monday after President Donald Trump posted an image on social media showing the island and other countries covered by the American flag, local broadcaster RUV said.
The map showed the United States, Canada, Greenland, Iceland, Mexico, Central America and the Caribbean covered by the US flag, with the entire landmass labelled "United States of America".
Trump posted the image on his Truth Social platform without explanation.
Iceland's Foreign Minister, Thorgerdur Gunnarsdottir, called in Billy Long, the US ambassador to Iceland, who only formally took up the post last month, RUV reported.
"The position was clearly expressed that the post was completely inappropriate," the foreign ministry told RUV.
The US State Department, the US embassies in Copenhagen and Reykjavik, and the US consulate in Nuuk did not immediately reply to requests for comment. The Icelandic foreign ministry also did not reply to a request for comment.
Trump's assertions in recent years that the US must acquire Greenland, a semi-autonomous Danish territory, sparked tensions between Washington and Copenhagen, both founding NATO members, and more broadly across Europe.
Iceland last month voted against reopening EU membership talks in a referendum where Trump's designs on Greenland had featured as a backdrop.
Some supporters of starting talks had cited concern about US reliability as a reason to consider closer EU ties, though analysts said domestic economic concerns ultimately drove the result.
Trump's post came hours after the European Commission announced a €200 million ($232.50 million) investment in Greenland during a visit by Commission President Ursula von der Leyen.
Danish Prime Minister Mette Frederiksen, speaking to Danish news agency Ritzau in Nuuk, said the message from Greenland's government and people had been consistent.
"The Greenlandic government and the Greenlandic people have said again and again that they do not want to be American," she said. "I hope no one is in any doubt about that, either in the United States or the rest of the world."
