The US president also refused to rule out pulling out of the bloc if it resists to cooperate

President Donald Trump has warned he may impose tariffs on US trading partners that do not support his push to acquire Greenland, escalating tensions with European allies and casting new uncertainty over NATO unity.

At a White House event on Friday, the US president doubled down on his campaign to bring the vast, mineral-rich Arctic island under US control - a goal he has pursued since his first term and renewed with vigor since returning to office last year. He has previously not ruled out using military force, stating that "one way or the other, we're going to have Greenland."

"I may put a tariff on countries if they don't go along with Greenland, because we need Greenland for national security," he said. "So I may do that."

Trump also refused to rule out pulling the US out of NATO if the bloc opposes his ambitions. "We're going to see," he said, noting that so far "NATO has been dealing with us on Greenland."

Trump claims that only US sovereignty can protect the Danish autonomous island from being taken over by Beijing or Moscow - an allegation dismissed by both countries.

European NATO members have largely refrained from direct public confrontation, but behind the scenes, resistance is mounting. This week, Denmark - which governs Greenland's foreign and defense policy - coordinated with several allies to send small contingents of troops to the island ahead of NATO's Arctic Endurance exercises. France, Germany, Sweden, Norway, and the United Kingdom contributed personnel, a move interpreted as a reinforcement of Greenland's existing sovereignty.

However, Denmark's top military commander in Greenland, Major-General Soren Andersen, dismissed any conflict between NATO allies as hypothetical. "I don't see a NATO ally attacking another NATO ally," he said. "My task is to work up here for the defence of the kingdom together with NATO."

NATO chief Mark Rutte declined to address the bloc's internal dispute. "I never ever comment when there are discussions within the alliance," he said.

Danish officials have expressed dismay, but the government's public response remains measured. After meetings in Washington this week, Danish Foreign Minister Lars Lokke Rasmussen acknowledged a "fundamental disagreement" with the US but expressed hope that a newly established "bilateral working group" would resolve the issue.