UK Prime Minister Sir Keir Starmer faces a "crimes against humanity" complaint at the United Nations over the treatment of the Chagossian people, as tensions rise after an Iranian missile attempt targeting Diego Garcia in the Indian Ocean.

Starmer, who is named in the filling, has been reported specifically over the removal of four people who returned to the island, in a complaint filed by the Attorney General for the Chagossian Government.

James Tumbridge's filing also comes as the exiled leadership stressed the importance of strong ties with the United States, telling Fox News Digital that Washington is a "brother in arms for global security."

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On March 20, Iran launched two ballistic missiles toward Diego Garcia from more than 2,300 miles away, missing the target but underscoring the base’s strategic importance.

Chagossian leaders have since backed continued U.S. presence, with First Minister Misley Mandarin saying they want to "uphold the 1966 agreement and consider the U.S. as a brother in arms for global security."

The 1966 agreement allowed the U.S. to use Diego Garcia for defense purposes, initially for 50 years.

"The desire of the Chagossian Government is to have a positive relationship with the U.S., and an ongoing presence on Diego Garcia of the U.S. military," Tumbridge also told Fox News Digital.

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Meanwhile, Tumbridge’s U.N. submission claims U.K. actions risk the "forced depopulation" of the Chagos Islands.

Expulsions began in 1968, when about 2,000 residents were removed, culminating in 1973, and in February the U.K. issued new removal orders to four Chagossians who had returned to the islands.

The filing calls the situation "forced displacement" that could constitute "a crime against humanity by forced depopulation of a territory."

It warns the British Government of a "fresh crime now" that could complete a decades-long erasure of the Indigenous population, stating, "The removal of these four persons would result in the total physical erasure of the Chagossian people," potentially "amounting to ethnic cleansing."

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"The BIOT commissioner accepted that the Chagossians were wronged in the past," Tumbridge said Wednesday.

"How can the U.K. prime minister, who claims to value the rule of law and human rights, not want to right that wrong and let the people return to their islands?" he added.

The filing also comes as the U.K. considers transferring sovereignty of the Chagos Islands to Mauritius.

This followed a 2019 International Court of Justice opinion, while preserving the Diego Garcia base under a 99-year lease.

President Donald Trump criticized the proposed handover, and the U.K. has since paused legislation to formalize the deal, with ministers saying it has become "impossible to agree at a political level."

The legislation was expected to be included in the King’s Speech outlining the next parliamentary session’s agenda.

Fox News Digital has reached out to 10 Downing Street for comment.