Trump, who takes office on January 20, said last week that U.S. control of Greenland was an “absolute necessity” and did not rule out using military or economic action such as tariffs against Denmark to make it happen.

“In the conversation, the prime minister referred to the statements of the Chairman of the Greenlandic Parliament, Múte B. Egede, that Greenland is not for sale,” Frederiksen’s office said in a statement.

“The prime minister emphasized that it is up to Greenland itself to make a decision on independence,” the statement said.

Frederiksen also emphasized the importance of strengthening security in the Arctic and that Denmark was open to taking greater responsibility, it added.