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.

The agreement ends decades of dispute over Britain’s last African colony, from which thousands of people were forcibly evicted, while maintaining a key U.S.-British military base there.