Washington said the deal protected the long-term, secure and effective operation of the strategic military base.

The U.K. has agreed to hand sovereignty of the long-contested Chagos Islands, an archipelago of more than 60 islands in the Indian Ocean, to Mauritius, in a deal to secure the future of a strategically important U.

In the early 1970s, Britain evicted almost 2,000 residents to Mauritius and the Seychelles to make way for an airbase on Diego Garcia, the largest island, which it had leased to the United States in 1966.