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.

After years of legal wrangling and negotiations, Britain said it would surrender sovereignty of the archipelago in the Indian Ocean.