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.

Britain struck a deal allowing it to keeping control of a strategically important UK-US military base in the Indian Ocean for another century, while ceding sovereignty over the Chagos Islands to Mauritius.

Britain said on Thursday it would give up sovereignty of the Chagos Islands to Mauritius in a deal that would allow people displaced decades ago to return home while London retained use of the important UK-U.