US President Donald Trump has threatened to place tariffs on nations that do not go along with his ambitions to annex Greenland.
Trump said at a White House meeting that he "may put a tariff on countries if they don't go along with Greenland", which is a self-governing territory controlled by Denmark.
He did not say which countries might be hit with new tariffs, or what authority he would invoke to use such import taxes in pursuit of his goal.
Along with Denmark and Greenland, other countries oppose his plans, and many in the US have expressed scepticism about an acquisition. As Trump spoke, a bipartisan congressional delegation was visiting Greenland to show support for the territory.
The 11-member group included Republicans who voiced concerns about the president's calls for the US to somehow acquire Greenland for national security reasons. They met MPs as well as Danish Prime Minister Mette Frederiksen and her Greenlandic counterpart Jens-Frederik Nielsen.
Group leader Senator Chris Coons, a Democrat, said their trip was to listen to the locals and take their views back to Washington "to lower the temperature".
Trump has said Greenland is vital for US security - and Washington would get it "the easy way" or "the hard way" - an apparent reference to buying the island or taking it by force.
"I may put a tariff on countries if they don't go along with Greenland, because we need Greenland for national security," Trump said at Friday's White House meeting on rural healthcare.
Greenland is sparsely populated but resource-rich and its location between North America and the Arctic makes it well placed for early warning systems in the event of missile attacks and for monitoring vessels in the region.
The US already has more than 100 military personnel permanently stationed at its Pituffik base - a missile-monitoring station on Greenland's north-western tip that has been operated by the US since World War Two.
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 needs to "own" it to defend it properly against possible Russian or Chinese attacks.
Denmark has warned that military action would spell the end of Nato - the trans-Atlantic defence alliance where the US is the most influential partner.
Nato works on the principle that allies have to aid each other in case of attack from outside - it has never faced an option where one member would use force against another.
European allies have rallied to Denmark's support.
They have also said the Arctic region is equally important to them and that its security should be a joint Nato responsibility - with the US involved.
To this end, several countries including France, Germany, Sweden, Norway, Finland, the Netherlands and the UK have dispatched a small number of troops to Greenland in a so-called reconnaissance mission.
French President Emmanuel Macron said "land, air, and sea assets" would soon be sent.
The visit of the US congressional delegation comes days after high-level talks in Washington failed to dissuade Trump from his plans.
They include senators and members of the US House of Representatives who are fervent supporters of Nato.
Though Coons and the majority of the group are Democratic staunch opponents of Trump, it includes moderate Republican Senators Thom Tillis and Lisa Murkowski.
Greenlandic MP Aaja Chemnitz said the meeting with US legislators had made her "hopeful". She told the BBC: "We need friends. We need allies."
Asked about the wide gulf between the view of the White House and the position of Greenland and Denmark, she said: "It's a marathon, not a short sprint.
"The pressure from the US side is something that we've seen since 2019. It would be naive to think that everything is over now."
She added: "It's changing almost hour by hour. So as much support as we can get, the better."
Murkowski is one of the sponsors of a bipartisan bill aimed at blocking any attempt to annex Greenland.
A Republican congressman has also introduced a rival bill in support of annexing the island.
Trump's envoy to Greenland, Jeff Landry, told Fox News on Friday the US should talk with Greenland's leaders, not Denmark.
"I do believe that there's a deal that should and will be made once this plays out," he said.
"The president is serious. I think he's laid the markers down.
"He's told Denmark what he's looking for, and now it's a matter of having Secretary [of State Marco] Rubio and Vice-President JD Vance make a deal.
"The United States has always been a welcoming party. We don't go in there trying to conquer anybody and trying to take over anybody's country.
"We say, 'Listen. We represent liberty. We represented economic strength. We represent protection.'"
The foreign ministers of Denmark and Greenland met Vance and Rubio at the White House on Wednesday.
According to a Danish official who spoke to the BBC on background to discuss the meeting, the US vice-president proposed finding a "middle ground" that would satisfy Trump and Denmark and Greenland.
The official said the possibility of a US military takeover of Greenland had not been raised in the White House meeting.
"We have never been in any discussions with any senior official or minister about the prospects of the United States sending in" troops to Greenland, the official said.
Still, the Danish official said Denmark was taking Trump's stated goal to seize Greenland seriously.
"It is our working hypothesis that on this issue what he says is what he means," the official said.
