Donald Trump has threatened to impose tariffs on countries that do not support his plan to control Greenland, citing US national security concerns.
Speaking at a White House event to promote investment in rural health, Trump drew comparisons to tariffs he had previously imposed on pharmaceutical imports from the European Union as part of efforts to lower drug prices in the US.
"I can do this for Greenland as well. I can put tariffs on countries that don't go along with us on the Greenland issue, because we need Greenland for national security," the president declared.
Meanwhile, a bipartisan group of US Congress members is visiting Denmark, in what is seen as a show of support in the face of growing pressure from Trump for the US to annex Greenland - a semi-autonomous region of Denmark in the Arctic.
The 11-member delegation will meet with MPs, as well as Danish Prime Minister Mette Frederiksen and her Greenlandic counterpart Jens-Frederik Nielsen.
The visit comes days after high-level talks in Washington failed to dissuade Trump from his plans.
Trump insists that Greenland is vital to US security - and that Denmark cannot protect it from potential Russian or Chinese attacks. Both Denmark and Greenland say they oppose a US invasion.
Greenland is sparsely populated but rich in resources, and its location between North America and the Arctic makes it well-positioned for early warning systems in the event of missile attacks and for monitoring ships in the region.
The US already has more than 100 military personnel permanently stationed at its Pituffik base - a facility that has been operated by the US since World War II.
Under existing agreements with Denmark, the US has the power to bring as many troops as it wants to Greenland.
But Trump has said the US must "own" it to properly protect it.
Denmark has warned that military action would mark the end of NATO.
NATO works on the principle that allies should help each other in the event of an external attack - it has never faced an option where one member would use force against another.
European allies have united in support of Denmark.