President Trump said Friday he could raise tariffs on countries that stand in the way of his effort to take control of Greenland. The warning came during remarks that were expected to focus on rural health care but quickly turned toward foreign policy.

He made clear he would not accept resistance from either allies or rivals when it comes to the Arctic island, which is a semi autonomous territory tied to Denmark, a NATO member. Trump framed the issue as a matter of U.S. interests rather than diplomacy.

Trump said: “I may put a tariff on countries if they don’t go along with Greenland.” He added: “We need Greenland for national security.” He did not explain how large the tariffs could be or when they might be imposed.

This was the first time Trump publicly tied tariffs to his Greenland push. He has previously refused to rule out the use of force to seize the island, which is rich in minerals and sits along key maritime routes near North America.

At the same time, the Supreme Court is reviewing a legal challenge to Trump’s tariff authority. The case questions whether tariffs justified by trade deficits can be used for political disputes unrelated to commerce.

The remarks came as lawmakers from both parties arrived in Denmark for meetings with Danish and Greenlandic officials. The visit underscored growing concern in Congress about the administration’s approach.

A number of Republican lawmakers have joined Democrats in rejecting the idea of taking Greenland. Resistance inside Washington has grown as allies continue to voice alarm.

Canada’s Prime Minister Mark Carney also criticized the proposal, saying Greenland’s population of about 57,000 people should decide their own future. He rejected any suggestion of purchase or invasion.

Earlier this week, officials from Denmark and Greenland met in Washington with Vice President JD Vance and Secretary of State Marco Rubio. The talks were described as tense, and little progress was made toward resolving the dispute.

The only agreement to come out of those meetings was the creation of a high level working group to keep discussions going. Both sides acknowledged the divide remains wide.

Several NATO countries, including France, Germany, and Sweden, have sent troops to Greenland alongside Danish forces. European officials have warned that any U.S. attack on Greenland would effectively break apart the NATO alliance.