Denmark’s prime minister has told the U.S. during a visit to Greenland that “you cannot annex another country,” even with the argument that international security is at stake.

The United States and Denmark offered drastically different perspectives regarding a meeting on the sidelines of the NATO conference happening in Brussels. Secretary of State Marco Rubio met with Danish Foreign Minister Lars Løkke Rasmussen in Brussels on Thursday amid the NATO foreign ministers’ meeting.

Danish Prime Minister Mette Frederiksen called on Thursday for increased Arctic defence collaboration with the United States during a visit to Greenland, and firmly dismissed the U.S. desire to annex the semi-autonomous Danish territory.