Greenland's flag flies in Igaliku settlement, Greenland, July 5, 2024. Reuters-Yonhap

EU foreign policy chief Kaja Kallas on Thursday said that Greenland's sovereignty must be respected after U.S. president-elect Donald Trump refused to rule out military action to seize the Arctic island.

"Greenland is part of Denmark," Kallas told journalists.

"We have to respect the territorial integrity and sovereignty of Greenland." Trump set off new alarm bells on Tuesday at a news conference when he refused to rule out military intervention over the Panama Canal and Greenland, both of which he has said he wants the United States to control.

The incoming U.S. leader has designs on the mineral- and oil-rich Arctic island, an autonomous territory of European Union member Denmark that itself has eyes on independence.

Kallas said she had spoken to Danish Prime Minister Mette Frederiksen after Trump's comments.

"She assured that the Danish and American relations have been very good," Kallas said.

"She also said that it's good that the president-elect takes an interest in the Arctic, which is a very important region, both for security but also for climate change."

Denmark's foreign minister on Wednesday said that Copenhagen was open to talks with the United States to safeguard U.S. interests in the Arctic.

Trump's broadside rocked Europe as it steels itself for a rocky ride after his inauguration on January 20.

German Chancellor Olaf Scholz insisted that "borders must not be moved by force. This principle applies to every country, whether in the East or the West."

"In talks with our European partners, there is an uneasiness regarding recent statements from the U.S. It is clear: We must stand together," he wrote in English on X. (AFP)