Denmark’s foreign minister said on Wednesday that a “fundamental disagreement” with U.S. President Donald Trump over the future of Greenland remained unresolved after high-level talks in Washington, even as Denmark and NATO allies moved to increase their military presence in the Arctic territory amid rising tensions.

Yesterday, after Greenland’s prime minister, Jens-Frederik Nielsen, vowed to cast his lot with Denmark over the United States, Trump said that he didn’t “know anything about” Nielsen but that such a choice would be a “big problem for him.”

Denmark and Greenland are stepping up their military presence on the island and allied reinforcements are expected to follow with Sweden confirming a deployment of military officers to the Arctic at Denmark’s request, according to a statement by prime minister Ulf Kristersson.

The U.S. and Denmark remain at odds over Greenland's future, Denmark's foreign minister said Wednesday following a tense White House meeting.

Follow Newsweek for live coverage of the worsening dispute between NATO allies the U.S. and Denmark over control of Greenland.

Veteran diplomat tells CBS News Denmark "ready to cooperate" on Greenland, and he expects U.S. to abandon "anachronistic approach of colonialism" post-Trump.

Denmark could trigger the European Union's little-known Article 42.7 if the U.S. attacks Greenland. But it would face high legal, political and military

Ask many key European leaders and officials, and they will tell you the US is the bedrock of the NATO alliance. A key issue is Article 5 in the treaty, which says an attack on one is an attack on all. With Greenland part of Denmark, and Denmark being a NATO member, this creates a clear problem.

The Arctic is no longer a distant frontier. Danish military aircraft have landed in Greenland, unloading troops as Copenhagen prepares for a potential standoff with the United States. What began as diplomatic friction has moved onto ice and airstrips,