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.

“We have always said we would only proceed with the deal if it has US support,” a UK government spokesperson said in a statement, according to the Reuters and AFP news agencies on Saturday.

This followed reports in the UK media that said a bill laying out plans to cede sovereignty of the 60-plus Indian Ocean islands had been dropped from the next parliamentary agenda, which starts on May 13.

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.

“We are continuing to engage with the US and Mauritius.”

The statement added that the UK “continue[s] to believe ⁠the agreement is the best way to protect ⁠the long-term future of the base”.

Mauritius, for its part, pledged not give up on repossession efforts.

Speaking at an Indian Ocean Conference hosted in Mauritius on Saturday, Foreign Minister Dhananjay Ramful said that his government would “spare no effort to seize any diplomatic or legal avenue to complete the decolonisation process in this part of the Indian Ocean”.

“This is a matter of justice,” he added.

‘Big mistake’

After Trump’s initial opposition, he appeared to momentarily back down in February after speaking with UK Prime Minister Keir Starmer, saying Starmer had made the “best deal he could make”.

But he then attacked the prime minister again on Truth Social weeks later.

“He is making a big mistake,” Trump wrote, adding that ceding the Chagos Islands would be “a blight on our Great Ally”.

Over the last six weeks, relations between Trump and Starmer have been further strained by the US-Israel war on Iran.

The UK is now leading a coalition of more than 30 countries to protect vessels in the Strait of Hormuz, without US participation in the initial talks.

Simon McDonald, who previously served as the UK Foreign Office’s most senior civil servant, told BBC Radio that Trump’s position forced the agreement to “go into the deep freeze for the time being”.

“When the president of the United States is openly hostile, the government has to rethink”, he said.

Britain has controlled the Chagos since 1814, including after Mauritius gained independence in the 1960s. The Diego Garcia base has played a key role in US military operations in Vietnam, Iraq and Afghanistan.

Chagossians – thousands of whom were forcibly evicted to make way for the base – have brought compensation claims to British courts, culminating in a 2019 International Court of Justice recommendation that the archipelago be returned to Mauritius.