The United Kingdom is setting aside a bill to return the Chagos Islands to Mauritius amid a lack of support from United States President Donald Trump, as Mauritius vows to “spare no effort” to reclaim the archipelago.

Last May, the UK and Mauritius jointly announced a deal that would return full sovereignty of Chagos to Mauritius, which is some 2,000 kilometres (1,200 miles) away from the archipelago.

Britain would then pay to lease Diego Garcia – the largest island and a strategic location in the middle of the Indian Ocean between Asia and Africa, which is home to the military base – on a 99-year lease to preserve US operations there.

But Trump opposed the move, calling it an “act of great stupidity” in January.

“Diego Garcia is a key strategic military asset for both the UK and the US. Ensuring its long-term operational security is and will continue to be our priority – it is the entire reason for the deal,” the UK government spokesperson added in his statement.