WASHINGTON -- The United States, Denmark and Greenland have agreed to establish a "high-level working group" to explore possible areas of compromise since a "fundamental disagreement" persists over the future of Greenland, Danish Foreign Minister Lars Lokke Rasmussen said here Wednesday.

His remarks came just after US Vice-President JD Vance and Secretary of State Marco Rubio met him and Greenlandic Foreign Minister Vivian Motzfeldt at the White House.

Though calling the meeting "a frank but also constructive" discussion "focused on how to ensure the long-term security in Greenland," Rasmussen said at a press conference that Denmark and Greenland's "perspectives continue to differ" from the United States.

"I must say, the president (US President Donald Trump) has made his view clear, and we have a different position," Rasmussen said, asserting that in Denmark's view, Greenland's long-term security "can be ensured inside the current framework."

"We agreed that it makes sense to try to sit down on a high level to explore whether there's possibilities to accommodate the concerns of the president while we at the same time, respect the red lines of the Kingdom of Denmark. So this is the work we will start," he said, adding that the working group is expected to meet for the first time "within a matter of weeks."

Rasmussen warned that "ideas that would not respect territorial integrity of the Kingdom of Denmark and the right of self-determination of the Greenlandic people are, of course, totally unacceptable."

Trump said Wednesday morning that anything less than Greenland becoming a part of the United States "is unacceptable," citing the need for US national security and the Golden Dome project.

On Tuesday, Danish Prime Minister Mette Frederiksen and Greenlandic Prime Minister Jens-Frederik Nielsen held a joint press conference in Copenhagen to show their united front against Trump's repeated threats to acquire the largest island in the world "one way or the other."

Nielsen said that if Greenland must choose between the US and Denmark, "we choose Denmark."

Frederiksen said her country is facing "completely unacceptable pressure" from its closest ally. "But there is much to suggest that the hardest part is still ahead of us."

Since his first term, Trump has repeatedly expressed a desire to acquire Greenland. Both Greenland and Denmark have made clear that the island is not for sale. The White House said last week that Trump will not rule out the use of force.

Greenland, the world's largest island, is a self-governing territory within the Kingdom of Denmark, while Copenhagen retains authority over defense and foreign policy. The United States maintains a military base on the island.