In a post on Truth Social, Trump said additional 10% import tariffs would take effect on February 1 on goods from Denmark, Norway, Sweden, France, Germany, the Netherlands, Finland and Britain - all already subject to tariffs imposed by Trump.

Those tariffs would increase to 25% on June 1 and would continue until a deal was reached for the U.S. to purchase Greenland, Trump wrote.

The president has repeatedly said Greenland is vital to U.S. security because of its strategic location and large mineral deposits, and has not ruled out using force to take it. European nations this week sent military personnel to the island at Denmark’s request.

“These Countries, who are playing this very dangerous game, have put a level of risk in play that is not tenable or sustainable,” Trump wrote.

“The United States of America is immediately open to negotiation with Denmark and/or any of these Countries that have put so much at risk, despite all that we have done for them, including maximum protection, over so many decades,” he said.

Protesters in Denmark and Greenland demonstrated on Saturday against Trump’s demands and called for it to be left to determine its own future.

Prominent European Union countries have backed Denmark, warning that the U.S. military seizure of a territory in NATO could collapse the military alliance that Washington leads. Britain has also given its support.