U.S. President Donald Trump linked his aggressive stance on Greenland to last year’s decision not to award him the Nobel Peace Prize, telling Norway’s prime minister that he no longer felt “an obligation to think purely of Peace,” two European officials said Monday.

Trump’s message to Jonas Gahr Støre appears to ratchet up a standoff between Washington and its closest allies over his threats to take over Greenland, a self-governing territory of NATO member Denmark. On Saturday, Trump announced a 10% import tax starting in February on goods from eight nations that have rallied around Denmark and Greenland, including Norway.

Those countries issued a forceful rebuke. But British Prime Minister Keir Starmer sought to de-escalate tensions on Monday. While the White House has not ruled out taking control of the strategic Arctic island by force, Starmer said he did not believe military action would occur.

“I think this can be resolved and should be resolved through calm discussion,” he said.

Still, the American leader’s message to Gahr Støre could further fracture a U.S.-European relationship already strained by differences over how to end the nearly four-year war in Ukraine, previous rounds of tariffs, military spending and migration policy.