THE HAGUE, Netherlands (AP) -- Mauritius told U.N. judges Monday that the Indian Ocean nation was strong-armed by former colonial power Britain into giving up part of its territory as a condition for gaining independence half a century ago, in a case that could have an impact on a strategically important U.S. military base.
The claim came as judges at the International Court of Justice began hearing arguments in a U.N. General Assembly request for an advisory opinion on the legality of British sovereignty over the Chagos Islands in the Indian Ocean that include Diego Garcia, home to a major U.S. military base.
"The process of decolonization of Mauritius remains incomplete as a result of the unlawful detachment of an integral part of our territory on the eve of our independence," Mauritius Defense Minister Anerood Jugnauth told judges.
Mauritius argues that the Chagos archipelago was part of its territory since at least the 18th century and was unlawfully taken by the U.K. in 1965, three years before the island nation gained independence. Britain insists it has sovereignty over the archipelago, which it calls the British Indian Ocean Territory.
Jugnauth said that during independence negotiations, then-British Prime Minister Harold Wilson told Mauritius' leader, Seewoosagur Ramgoolam, that "he and his colleagues could return to Mauritius either with independence or without it and that the best solution for all might be independence and detachment (of the Chagos Islands) by agreement."
Ramgoolam understood Wilson's words "to be in the nature of a threat," Jugnauth said.
The U.K. sealed a deal with the U.S. in 1966 to use the territory for defense purposes. Washington maintains a forward operating location there for aircraft and ships that contribute to regional and global security.
Jugnauth said that the base shouldn't be affected by the court's ruling.
"Mauritius has been clear that a request for an advisory opinion is not intended to bring into question the presence of the base on Diego Garcia," he told judges. "Mauritius recognizes its existence and has repeatedly made it clear to the United States and the administering power that it accepts the future of the base."
Britain was due to address the court later Monday. The U.S., which has backed Britain on the issue, is among about 20 other nations and the African Union due to speak in the case this week.
Judges are expected to take months to issue their advisory opinions on two questions: Was the process of decolonization of Mauritius lawfully completed in 1968 and what are the consequences under international law of the U.K.'s continued administration, including with respect to the inability to resettle Chagos residents on the islands?
Britain evicted about 2,000 people from the Chagos archipelago in the 1960s and 1970s so the U.S. military could build an air base on Diego Garcia. The islanders were sent to the Seychelles and Mauritius, and many eventually resettled in the U.K.
The Chagossians have fought in British courts for years to return to the islands. In 2016, the Supreme Court rejected their most recent appeal.
A small group of Chagossians protested outside the court Monday holding banners including one that read: "Chagossian sacrifice to protect the world but our reward is slow death."