Danish Prime Minister Mette Frederiksen warned on Monday that a U.S. military takeover of Greenland would effectively end NATO, responding to renewed comments by President Donald Trump suggesting the United States should control the Arctic territory.

Frederiksen’s remarks came amid heightened global unease following a U.S. operation over the weekend that captured Venezuelan President Nicolás Maduro. The episode has intensified concerns in Denmark and Greenland, a semi-autonomous territory within the Danish kingdom and a NATO member by extension.

“If the United States chooses to attack another NATO country militarily, then everything stops,” Frederiksen told broadcaster TV2. “That is, including our NATO and thus the security that has existed since the end of the Second World War.”

Trump has repeatedly raised the idea of U.S. jurisdiction over Greenland since his transition back into office and has refused to rule out the use of force. His latest comment, “let’s talk about Greenland in 20 days”, fueled fears of imminent action.

Frederiksen said Trump “should be taken seriously” and stressed that Denmark and Greenland would not accept threats to their sovereignty.

Greenland’s Prime Minister Jens Frederik Nielsen also rejected comparisons with Venezuela and urged calm. “The situation is not such that the United States can simply conquer Greenland,” he said, adding that Greenland wants cooperation, not confrontation.

Trump has criticized Denmark’s security presence on the island, mocking its defenses and claiming Greenland is strategically vital due to alleged Russian and Chinese activity. However, Danish security experts have disputed those claims.

Tensions were further inflamed by a social media post from a former Trump administration official depicting Greenland draped in U.S. flag imagery with the caption “SOON.”

Despite the dispute, the U.S. maintains a longstanding military presence at Greenland’s Pituffik Space Base under a 1951 defense agreement, and Denmark remains a close U.S. ally, hosting American forces and purchasing U.S. military equipment, even as critics warn that recent agreements risk eroding Danish sovereignty.