Argentina has promised to gain “full sovereignty” of the Falkland Islands with “concrete action” after Britain surrendered control of the Chagos Islands. The country’s foreign minister, Diana Mondino,

The Falklands remain safe in British hands, governor Alison Blake has said after the UK agreed to give sovereignty of the Chagos Islands to Mauritius.

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.

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 British government made the deal to return all the Chagos Islands, except for Diego Garcia, which holds a U.K.-U.S. Navy base.

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 retains use of the UK-U.S.

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

The UK has announced it is giving up sovereignty of a remote but strategically important cluster of islands in the Indian Ocean after more than half a century. The deal – reached after years of negotiations - will see the UK hand over the Chagos Islands to Mauritius in a historic move.