Foreign Secretary David Miliband said commercial fishing will be halted around the Chagos Islands to allow scientific research and the preservation of coral reefs and an estimated 60 endangered species.

His ministry insisted the move would not affect operations on the island of Diego Garcia, which Britain leases to the US military for use as a base. Miliband told lawmakers in 2008 that the US had belatedly informed Britain it had used Diego Garcia as a stop for CIA extraordinary rendition flights.

Conservation groups and scientists welcomed the move to protect waters around the islands, reputedly some of the world's cleanest ocean, and claimed it would become as important for research as the Great Barrier Reef or Galapagos Islands.

"The territory offers great scope for research in all fields of oceanography, biodiversity and many aspects of climate change, which are core research issues for UK science," Miliband said Thursday, announcing the decision.

Halfway between Africa and Southeast Asia, the Chagos Islands have been frequently controversial for the British government.

The European Court of Human Rights is considering a long running appeal from Chagossians evicted from their homes to nearby Mauritius between 1967 and 1973 to make way for the military base. Islanders are seeking to return to their former homes.

"The creation of this marine reserve is a first step toward securing a better and sustainable future for the Chagos Islands," said Greenpeace activist Willie Mackenzie. "But this future must include securing justice for the Chagossian people and the closure and removal of the Diego Garcia military base." Miliband said the protected zone would cover 210,000 square miles (544,000 square kilometers) of ocean, which is home to about 220 types of coral, 1,000 species of fish and 33 different seabirds.

The Chagos Environment Network - a coalition of ocean scientists - said the area will replace the Papahanaumokuakea Marine National Monument, in Hawaii, as the world's largest marine reserve.

Miliband said Britain has agreed to transfer control of the territory to Mauritius "when it is no longer needed for defense purposes," but has not specified any timeframe.

Under the terms of the lease of Diego Garcia, the US military can remain on the island until at least 2036.