Denmark agreed on Friday to discuss the Arctic region with Washington, the foreign minister said Lars Locke Rasmussen, after the first telephone communication with the top diplomat of the president’s administration Donald Trumpwho wants control of her Greenland.

Rasmussen and the US Secretary of State Marco Rubio they had a 20 minute chat in “good and constructive tone”they discussed Ukraine, European security and the situation in the Middle East, Denmark’s foreign ministry said in a statement.

The State Department said late Friday that Rubio “reaffirmed the strength of the relationship” between the two countries in the call.

Trump has expressed interest to make Greenlandan autonomous territory of Denmark, part of the United States. He has not ruled out using military or economic force to persuade Denmark to hand it over.

Greenland’s strategic location along the shortest route from Europe to North America, vital to the US ballistic missile warning system, has made it priority for Trump.

The Prime Minister of Denmark, Mete Fredericksenon Jan. 15 said he spoke on the phone with Trump and told him it was up to Greenland itself to decide on any independence.

The Financial Times reported on Friday that last week’s call between Frederiksen and Trump was “heated”, with Trump insisting he was serious about his determination to take over Greenland. The newspaper cites European officials. Trump took office on January 20.

“Arctic security was not on the agenda, but it was agreed that will be discussed between the United States, Denmark and Greenland at a later date”the Danish ministry said on Friday.

The Prime Minister of Greenland, Mute Egedewho has stepped up efforts for independencehas repeatedly stated that the island is not for sale and that it is up to its residents to decide their future.

While Trump had expressed the possibility of taking over Greenland in 2019 during his first term in the White House, his refusal to rule out the use of military or economic force has surprised many Danes.