Trump slams UK island handoff deal that could put key US military base at risk

President Donald Trump dramatically reversed course Tuesday on a U.K. plan to transfer sovereignty of the Chagos Islands to Mauritius while warning it could jeopardize U.S. access to the Diego Garcia military base. Trump’s reversal highlights what a defense expert called a "new Trump Doctrine" before linking the president's opposition to the Chagos deal with his Greenland push and citing fears Mauritius could later back out. Writing on his Truth Social platform Tuesday, Trump called the U.K.’s Chagos decision "an act of great stupidity." "Shockingly, our ‘brilliant’ NATO Ally, the United Kingdom, is currently planning to give away the Island of Diego Garcia, the site of a vital U.S. Military Base , to Mauritius, and to do so FOR NO REASON WHATSOEVER," Trump wrote. "There is no doubt that China and Russia have noticed this act of total weakness." TRUMP ISSUES STERN WARNING TO NATO AHEAD OF VANCE'S HIGH-STAKES Greenland MEETING "Trump has done a 180, partly because of the U.K.’s support for Denmark’s sovereign claims over Greenland and partly because of a new strategy outlined by the White House," John Hemmings, director of the National Security Center at the Henry Jackson Society , told Fox News Digital. "These moves are linked and part of a ‘new Trump Doctrine’" outlined in November’s National Security Strategy," he explained. "Diego Garcia is a potential threat to Beijing’s strategy to control vital shipping lanes between the oil-rich Middle East and China’s industrial heartland," he added, describing how "nearly 23.7 million barrels of oil transit the Indian Ocean every day, with the base being vital in any U.S.-China conflict over Taiwan." TRUMP TELLS DAVOS US ALONE CAN SECURE Greenland, INSISTS HE WON’T 'USE FORCE' In a separate post, Trump explicitly linked the Chagos dispute to his Greenland push. "The U.K. giving away extremely important land is an act of GREAT STUPIDITY, and is another in a very long line of national security reasons why Greenland has to be acquired," Trump wrote. The Chagos Islands were separated from Mauritius during Britain’s decolonization process, a move the International Court of Justice ruled unlawful in 2019. The U.K. later agreed to transfer sovereignty while leasing Diego Garcia back for at least 99 years at a cost of at least $160 million annually. Diego Garcia is a hub for long-range bombers, logistics and power projection across the Middle East, the Indo-Pacific and Africa. Around 2,500 personnel, mostly American , are stationed there. TRUMP DOUBLES DOWN ON Greenland PUSH AS POLLS SHOW LITTLE PUBLIC SUPPORT "If Mauritius were to offer the islands to China after taking de jure control, it would put immense pressure on the U.S. in the eyes of international public opinion," Hemmings explained. "After all, once Mauritius has de jure sovereignty , it can renegotiate the lease terms or even renege on the treaty at any time it wants. "It might also provide access to the exclusive economic zone, with all of its rich fishing grounds, to Chinese fishing fleets , adding another layer of risk to U.S. Air Force operations around the island," Hemmings said. "At this moment, the U.S. base at Diego Garcia is thought to be secure, with Mauritius promising the U.K. (and by proxy, the U.S.) a 99-year lease, which will not, it is supposed, interfere with the operations of the air base at all. But the devil is in the details." Fox News Digital has reached out to the White House for comment.