Greenland is a self-ruling territory in the Danish kingdom, which means policymakers in Nuuk control most domestic issues. Denmark, which oversees defense and security policy on the mineral-rich Arctic island, is injecting 14.6 billion kroner ($2 billion) to ramp up defenses.

President Trump reportedly held a “fiery” call with Denmark’s Prime Minister Mette Frederiksen over the president’s insistence that U.S. control of Greenland is necessary for American national security.