U.S. President Donald Trump has cautioned U.K. Prime Minister Keir Starmer against transferring sovereignty of the Chagos Islands to Mauritius, stating it could expose Britain to a possible assault from what he termed a “highly unstable and dangerous” Iranian government.
The island of Diego Garcia, part of the Chagos archipelago, hosts a strategically important joint U.K.-U.S. military installation—a point Trump highlighted in his remarks.
“If Iran chooses not to reach an agreement, the United States may need to utilize Diego Garcia and the airfield in Fairford to eliminate a potential attack from a highly unstable and dangerous regime—an attack that could target the United Kingdom, along with other allied nations,” Trump stated.
Labeling Starmer’s approach a “big mistake,” Trump insisted the British leader “must not lose control, under any circumstances, of Diego Garcia.”
This warning emerges amid increasing speculation about potential military action against Iran.
As tensions rise, the United States has intensified its military presence in the area. U.S. officials participated in discussions in Geneva with Iranian representatives regarding Tehran’s nuclear program this week, but the sides remain “very far apart on some issues,” according to White House press secretary Karoline Leavitt.
TIME has reached out to the White House for additional comment.
The Chagos Islands were established as British territory in 1814, when they were handed over to the U.K. together with Mauritius. The islands were detached from Mauritius in 1965, while it was still a British colony, and were purchased by the U.K. as an overseas territory for approximately £3 million ($4 million). Since Mauritius achieved independence from the U.K. in 1968, its government has maintained that it was unlawfully compelled to cede the territory to gain independence from Britain. Under an agreement finalized last year, the U.K. consented to hand over sovereignty to Mauritius while simultaneously leasing back the strategically critical Diego Garcia base.
“Starmer is losing control of this important island due to claims from entities previously unheard of. In our view, they are fictitious,” Trump said Wednesday, adding that if the agreement proceeds, it will be a “blight” on the U.K.
In a statement to TIME, a U.K. Foreign Office spokesperson said: “The agreement to ensure the future of the joint U.K.-U.S. military base on Diego Garcia is essential for the security of the U.K. and our key allies, and for the safety of the British people. The arrangement we have made is the sole method to secure the long-term viability of this crucial military base.”
On Thursday, U.K. lawmaker Alex Davies-Jones stated that the U.K. will proceed with the legislation, irrespective of Trump’s reservations.
“We will continue to collaborate with our allies, including the United States, on this matter, but the overriding priority must be national security, and that is what this government is committed to achieving,” she told Times Radio.
Trump’s opposition to the lease agreement seems to conflict with a statement released by the U.S. State Department on Feb. 17, which explicitly voiced support for the U.K.’s choice to move forward with its agreement with Mauritius regarding the Chagos Archipelago.
Trump’s personal view on the deal has changed over recent months.
When Starmer visited Washington in February 2025, Trump expressed his belief that it would “work out very well” and characterized the proposed lease as “a very long-term, powerful lease.”
However, in January, while reinforcing his effort to acquire Greenland, he criticized the U.K.’s geopolitical decision, labeling the islands agreement “an act of great stupidity” and one of “total weakness.”
Trump moderated his firm position a few days later, explaining that he had conversed with Starmer and recognized the deal was “the best he could make.”
“Nevertheless, if the lease agreement ever collapses in the future, or if anyone menaces or jeopardizes U.S. operations and forces at our base, I reserve the right to militarily secure and reinforce the American presence in Diego Garcia,” he cautioned.
Trump’s most recent statements precede upcoming discussions between the U.S. State Department and Mauritius concerning the strategic base at Diego Garcia.
