President Donald Trump cautioned the British government on Wednesday against relinquishing control of the strategically vital Diego Garcia base in the Indian Ocean, arguing that the United States may require the facility if Iran declines to reach an agreement with Washington.

In a post on Truth Social, Trump pointed to the military importance of the island and a separate airfield in the United Kingdom, writing, “Should Iran decide not to make a deal, it may be necessary for the United States to use Diego Garcia, and the Airfield located in Fairford, in order to eradicate a potential attack by a highly unstable and dangerous regime.”

Trump added that any such strike could be aimed at protecting Britain as well as other allied nations, warning that the threat would extend to the UK and other “friendly countries.”

The president sharply criticized Prime Minister Keir Starmer over a recently signed lease arrangement concerning the island, arguing that sovereign territory should not be handled through long-term leasing agreements. He described the decision as a “big mistake.”

“Prime Minister Starmer should not lose control, for any reason, of Diego Garcia, by entering a tenuous, at best, 100 Year Lease,” Trump wrote.

He further asserted that Britain is effectively surrendering authority over the strategically located island due to what he described as questionable claims by unfamiliar parties. Calling those claims fabricated, Trump stated, “This land should not be taken away from the U.K. and, if it is allowed to be, it will be a blight on our Great Ally.”

Trump emphasized that the United States stands firmly behind Britain militarily but said the UK must demonstrate resolve. He declared that America would remain prepared to defend its ally while urging British leaders to stay strong “in the face of wokeism, and other problems put before them.”

“Do not give away Diego Garcia,” he said.

White House spokesperson Karoline Leavitt reinforced the president’s message, saying the post “should be taken as the policy of the” Trump administration.

Diego Garcia, the largest island in the Chagos Archipelago, has functioned as a joint British-American military installation since the 1970s. Under a treaty finalized in May, sovereignty over the Chagos Islands will shift from the United Kingdom to Mauritius, while the military base itself is set to remain under British control for a minimum of 99 years.

Trump’s warning comes at a time of rising friction between Washington and Tehran and a major expansion of U.S. forces in the Middle East as diplomatic talks continue.

Earlier this year, Trump came close to approving an additional military strike following Iran’s crackdown on protesters. He ultimately held back after Tehran halted the executions of demonstrators.