U.S. president-elect Donald Trump on Tuesday said he would not rule out the use of military force to seize control of the Panama Canal and Greenland, as he declared U.S. control of both to be vital to American national security.

Speaking to reporters less than two weeks before he takes office on Jan. 20 and as a delegation of aides and advisers that includes his son Donald Trump Jr. is in Greenland, Trump left open the use of the American military to secure both territories.

“I’m not going to commit to that,” he said, when asked if he would rule out the use of the military. “It might be that you’ll have to do something. The Panama Canal is vital to our country.” He added, “We need Greenland for national security purposes.” Greenland is an autonomous territory of Denmark, a longtime U.S. ally and a founding member of NATO.