The United States, Denmark and Greenland signed a new security agreement at the United Nations headquarters in New York on September 22, 2026, to strengthen defence cooperation in the Arctic and North Atlantic regions. The agreement was signed by US President Donald Trump, Danish Prime Minister Mette Frederiksen and Greenland Prime Minister Jens-Frederik Nielsen. The pact allows the US to expand its existing Pituffik Space Base and establish two additional defence areas in Greenland at Narsarsuaq and Mestersvig. It also strengthens NATO’s role in Arctic security, restricts military installations by non-NATO countries and introduces tighter scrutiny of certain foreign investments in sensitive sectors. The agreement reaffirms Denmark’s sovereignty over Greenland and recognizes the Greenlandic people’s right to self-determination. It will take effect after the required parliamentary procedures are completed.