U.S. President Donald Trump on Monday reiterated that the United States should own Greenland, rejecting Denmark’s claim to the island and reviving a stance that has strained relations with Europe in the past.

“Just because a ship went there 500 years ago and then left, that doesn’t give you ownership of the land,” Trump said, referring to Denmark’s historical claim over Greenland.

Trump also said in a social media post that he had a “very pleasant” phone call with NATO Secretary General Mark Rutte on the issue of Greenland, underscoring the strategic importance of the Arctic territory amid rising geopolitical tensions.