President Donald Trump is considering “a range of options” to acquire Greenland including the use of military force, the White House said Tuesday, raising the stakes just hours after several top European leaders declared that such a move would violate NATO’s core charter.

Trump “has made it well known that acquiring Greenland is a national security priority of the United States, and it’s vital to deter our adversaries in the Arctic region,” White House press secretary Karoline Leavitt said in a statement. “The President and his team are discussing a range of options to pursue this important foreign policy goal, and of course, utilizing the U.S. Military is always an option at the Commander in Chief’s disposal.”

Following Saturday’s special forces operation to remove former Venezuelan leader Nicolás Maduro from power, Trump has repeatedly asserted his view that the U.S. has the prerogative to do whatever it deems necessary to advance its security and economic interests across the Western Hemisphere, threatening specific actions against Colombia, Cuba, Mexico and Greenland.

The president’s comments about Greenland in particular have sparked panic across Scandinavia and the rest of Europe given the potential implications for a continent already scrambling to shore up its defense against Russia.

A U.S. invasion of Greenland, a Danish territory, would amount to a shocking violation of NATO’s Article V, which declares an attack on any member of the 32-nation alliance an attack on all. A breach of Denmark’s territorial sovereignty by the U.S., which has been a linchpin of the organization since its founding following World War II, would effectively end the transatlantic alliance.

Trump has said that acquiring Greenland, an icy land mass between the Arctic Ocean and the North Atlantic, is a national security imperative. Denmark has communicated its openness to a heightened U.S. military presence there, but the president has appeared uninterested in anything less than a full U.S. takeover.

In their statement earlier Tuesday, the leaders of Denmark, Great Britain, France, Germany, Italy, Spain and Poland declared a shared belief that “security in the Arctic must be … achieved collectively, in conjunction with NATO allies including the United States by upholding the principles of the UN Charter, including sovereignty, territorial integrity and inviolability of borders.”