The bipartisan bill would bar funding for any move to occupy or annex the territory of a NATO member state.

US senators have introduced a bill aimed at preventing President Donald Trump from seizing NATO territory, including the self-governing Danish island of Greenland.

The bipartisan NATO Unity Protection Act introduced on Tuesday would bar the Department of Defense and Department of State from using funds to “blockade, occupy, annex or otherwise assert control” over the territory of any NATO member state.

The bill, authored by Democrat Jeanne Shaheen and Republican Lisa Murkowski, comes amid growing concerns over Trump’s repeated insistence that Greenland, a semi-autonomous territory of Denmark, must be brought under Washington’s control, using force if necessary.

“This bipartisan legislation makes clear that US taxpayer dollars cannot be used for actions that would fracture NATO and violate our own commitments to NATO,” said Shaheen, who represents the state of New Hampshire, in a statement.

“This bill sends a clear message that recent rhetoric around Greenland deeply undermines America’s own national security interests and faces bipartisan opposition in Congress,” the Democratic senator said.

Murkowski, a rare Republican critic of Trump who represents Alaska, said the 32-member NATO security alliance was the “strongest line of defence” against efforts to undermine global peace and stability.

“The mere notion that America would use our vast resources against our allies is deeply troubling and must be wholly rejected by Congress in statute,” Murkowski said.

Trump’s threats to take control of Greenland have alarmed Washington’s European allies and prompted warnings about the end of NATO, which is built on the principle that an armed attack against any one member is considered an attack against all.

Trump, who claims that control of the vast Arctic territory is crucial to US national security, has brushed aside concerns about splitting the alliance, which has been a cornerstone of the Western-led security order since the end of World War II.

Trump has also claimed that China or Russia would take control of Greenland, which is home to vast reserves of fossil fuels and critical minerals, if the US does not.

“I’d love to make a deal with them. It’s easier,” Trump said on Sunday of his plans for the territory.

“But one way or the other, we’re going to have Greenland.”

In a rebuke to Trump, Danish Prime Minister Mette Frederiksen and Greenland’s prime minister, Jens-Frederik Nielsen, on Tuesday offered some of their most forceful comments yet in defence of Copenhagen’s sovereignty over the territory.

“If we have to choose between the United States and Denmark here and now, we choose Denmark,” Nielsen said at a joint news conference in Copenhagen.

“We choose NATO. We choose the Kingdom of Denmark. We choose the EU,” he said.

Danish Minister for Foreign Affairs Lars Lokke Rasmussen and his counterpart in Greenland, Vivian Motzfeldt, are on Wednesday set to meet with US Secretary of State Marco Rubio and US Vice President JD Vance in Washington, DC, for talks on the escalating crisis.

A bipartisan delegation of US lawmakers, including Democratic Senator Chris Coons and Republican Senator Thom Tillis, is set to arrive in Denmark on Friday for talks with local officials.

The vast majority of Greenland’s 57,000 residents have expressed opposition to US control of the territory, according to polling.

In a survey commissioned by the Danish paper Berlingske last year, 85 percent of residents said they did not wish to join the US, with just 6 percent in favour.