Washington DC - President Donald Trump on Tuesday slammed the UK for its "great stupidity" in agreeing to a deal transferring sovereignty over the Chagos Islands in the Indian Ocean to Mauritius.

"The UK 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," the Republican posted on Truth Social.

The comments mark a major change of position for Trump, who's administration fully and publicly endorsed the deal in May.

The agreement will see Britain hand back the archipelago to its former colony and pay to lease a key US-UK military base on Diego Garcia, the largest island.

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Britain kept control of the Chagos Islands after Mauritius gained independence in the 1960s, evicting thousands of Chagos islanders who have since mounted a series of legal claims for reparations in British courts.

In 2019, the International Court of Justice recommended that Britain hand the archipelago to Mauritius after decades of legal battles.

"There is no doubt that China and Russia have noticed this act of total weakness," Trump raved in the post. "These are International Powers who only recognize STRENGTH, which is why the United States of America, under my leadership, is now, after only one year, respected like never before."

The 79-year-old has sparked an international crisis through by repeatedly announcing his intention to seize Greenland, a an autonomous territory of NATO member Denmark.

European countries taking part in World Economic Forum in Davos Tuesday are set to discuss potential responses to Trump's threats of imposing punishing tariffs on allies who oppose his landgrab.