Donald Trump has criticised the UK's plans to hand over the sovereignty of the Chagos Islands to Mauritius, claiming it's "an act of great stupidity."
The US president, who previously backed the deal in May, took to his Truth Social account to criticise the agreement.
He writes: "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.
"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.
"Denmark and its European Allies have to DO THE RIGHT THING. Thank you for your attention to this matter. PRESIDENT DONALD J. TRUMP."
The signed agreement would see the UK hand over its sovereignty of the Chagos Islands to Mauritius, while retaining control of a UK-US military base on Diego Garcia. The 99-year agreement is expected to cost the UK £101million a year.
Mr Trump says the deal is one of the reasons he wants the US to take over Greenland.