Danish Foreign Minister Lars Løkke Rasmussen warned that the future of the international system and NATO itself is at risk, amid U.S. President Donald Trump’s statements threatening tariffs on nations opposing his push to bring Greenland under American control.

During a visit to Norway, Rasmussen said the European Union is capable of resisting U.S. pressure if member states unite behind a common stance.

NATO Secretary General Mark Rutte said he is closely monitoring developments and plans to raise the issue with Trump during the Davos World Economic Forum.