President Trump restated his belief this week that Greenland will eventually become part of the United States. “I think it’ll happen,” Trump said when asked by a reporter about the possible U.S. annexation of the massive but sparsely populated Arctic island during an Oval Office meeting with NATO Secretary-General Mark Rutte on Thursday.

President Donald Trump told NATO Secretary-General Mark Rutte on Thursday that U.S. control of Greenland is necessary to enhance international security, escalating his campaign to annex the strategic Arctic island.

Both Canada and Greenland, which is included in NATO as the territory of founding member Denmark, were raised during an informal press conference in the Oval Office. In the meeting, Trump also applied new pressure on the trans-Atlantic alliance to spend more on its collective defense.