Donald Trump has slammed UK Prime Minister Keir Starmer for agreeing to return the Chagos Islands to Mauritius while leasing back Diego Garcia. On Wednesday, Trump called it “a big mistake” and warned on Truth Social that Starmer was “losing control of this important Island by claims of entities never known of before,” which he called fictitious. The Chagos Islands, a UK territory since 1814, include Diego Garcia, home to a key US-UK military base. Britain had forced residents to leave to build the base, which Mauritius has long contested. Following a 2019 International Court of Justice ruling and a UN resolution, the UK agreed to transfer sovereignty to Mauritius. However, the UK will keep a 99-year lease with an option to extend, costing about £100 million ($135m) a year. A UK Foreign Ministry spokesperson called the deal “crucial to the security of the UK and our key allies.” Trump, who opposed the deal in January, said after a recent call with Starmer that it was “the best deal he could” make. He warned the base in Diego Garcia and an airfield in Fairford might be vital to stop possible attacks from Iran, which could also threaten the UK and friends. Trump added the UK must “remain strong in the face of Wokeism, and other problems put before them.” Meanwhile, displaced Chagossians, many now living in Mauritius, Seychelles, and the UK, continue to fight to return to their homeland.