LONDON — Donald Trump has blasted Britain’s decision to hand control of the Chagos Islands to Mauritius as an act of “great stupidity” without any justification.

The U.S. president, who previously backed the deal, said Tuesday there is “no doubt” Russia and China have noticed the “act of total weakness.”

The U.K. agreed to hand the strategically important archipelago in the Indian Ocean to Mauritius in May 2025.

“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 U.S. president posted on Truth Social.

“There is no doubt that China and Russia have noticed this act of total weakness. These are international powers who only recognize strength,” Trump claimed, adding Britain “giving away extremely important land is an act of great stupidity.”

The president said the U.K.’s Chagos decision justified his desire to acquire Greenland — a move NATO allies, including the U.K., have vehemently opposed.

The agreement would pass sovereignty of the islands to Mauritius, whose government long claimed it was forced to give up the islands for its own independence from Britain in 1968.

However, the Diego Garcia military base will remain under U.K. and U.S. control for the next 99 years.

Trump told Prime Minister Keir Starmer last February Washington, D.C. would “be inclined to go along” with Britain, while U.S. Secretary of State Marco Rubio “welcomed the historic agreement” when the deal was signed in May 2025.

Chief Secretary to the Prime Minister Darren Jones said Tuesday Britain “can’t reverse the clock.” The treaty has “been signed” with the Mauritian government, he told Times Radio.

The Diego Garcia Military Base and British Indian Ocean Territory Bill, which implements the treaty’s provisions in British law, returns to the House of Commons Tuesday afternoon for its final stages of legislative scrutiny.