US Secretary of State Marco Rubio has told lawmakers that President Donald Trump plans to buy Greenland rather than invade it, while  Trump has asked aides to give him an updated plan for acquiring the territory, US officials said on Tuesday, reports The New York Times.

Rubio made his remarks in a briefing on Monday with lawmakers from the main armed services and foreign policy committees in both chambers of Congress. The same day, Trump told aides to deliver an updated plan.

The congressional briefing was focused on Venezuela, but lawmakers raised concerns about Trump’s intentions on Greenland given aggressive remarks this week by the American president and a top aide, Stephen Miller, two officials said.

Rubio did not go into detail on what he meant by buying Greenland.

On Tuesday, leaders of six NATO nations joined with Mette Frederiksen, the prime minister of Denmark, to issue a joint statement pushing back against Trump’s assertions that the US should take over Greenland.

Greenland is a sparsely populated, autonomous territory that falls under the sovereign boundaries of Denmark, a member of NATO. Denmark established colonial control over Greenland in the 18th century, and allowed it to become autonomous in the 20th century.