US President Donald Trump on Wednesday doubled down on his persistent ambition to acquire Greenland, after Danish Prime Minister Mette Frederiksen had insisted only moments earlier that the vast Arctic territory was “not for sale.”

“Greenland is a big problem for us,” Trump said at the start of the second day of the NATO summit in Ankara, adding that he would bring up the issue during consultations with leaders later on Wednesday.

“Greenland is very important for the United States, but it’s not important for Denmark,” Trump said.

The president said the US shouldn’t have given the territory back to Denmark after the end of World War II, when Greenland fell under the protection of the US after Denmark was occupied by Nazi Germany.

“We need it for protection of the world, not just the United States,” Trump said.

Asked by reporters to comment on the row after arriving at the summit venue on Wednesday morning, Frederiksen stressed that the ice-covered island administered by the Kingdom of Denmark was “not for sale.”

“We hope that all, including all allies, will respect the Greenlandic people’s right for self-determination. And we are a sovereign state, and we need everybody to respect our territorial integrity and our sovereignty,” she added.

Trump reignites row

Frederiksen was responding to comments made by Trump at the start of the NATO summit on Tuesday, reiterating that Greenland “should be controlled by the United States, not by Denmark.”

Earlier this year, Trump openly threatened to take over the strategically important island, not only alienating NATO ally Denmark but also raising doubts about the cohesion of the world’s largest military alliance and mutual loyalty within NATO.

He justified his ambitions by arguing that Greenland would otherwise not be safe from Russia and China and therefore posed a risk to US security interests.

Trump later withdrew the threat to use military force if necessary and dropped the announcement of punitive tariffs against Germany and other European countries if they did not agree to sell the island to the US. However, he stuck to his claims to the island. The governments of Denmark and Greenland have consistently rejected US annexation.

Nordic allies back Denmark

NATO Secretary General Mark Rutte, who previously mediated in the dispute, said the alliance had “a good process in place” regarding Denmark and Greenland.

In February, Denmark, Greenland and the US started talks on a potential future agreement on ensuring security in the Arctic through joint actions by the US and Arctic allies. In addition, allies enhanced their presence in Greenland.

Rutte stressed that Trump remained “completely committed” to NATO despite differences over Greenland, defence spending and the war in Iran.

Nordic NATO allies rallied behind Copenhagen on Wednesday, stressing that it was for Greenland and Denmark to determine the territory’s future.

Icelandic Prime Minister Kristrún Frostadóttir said that “Greenland belongs to the people of Greenland. They do not wish to be a part of the United States.”

“What we need now is unity. We have threats coming from outside the alliance,” she said, pointing to Russia. “We need to focus on us and how we stick together.”

Finnish President Alexander Stubb stressed that “matters of Greenland are linked and only in the hands of the Kingdom of Denmark.”

Noting that discussions were being held between the US, Denmark and Greenland, he added that several NATO countries, including Finland, had “Arctic know-how” that could help to secure the region.