Mauritius's prime minister said Tuesday that his country had reached a newly renegotiated deal with Britain over control of the strategic Chagos Islands but was awaiting US President Donald Trump's opinion.

Britain and its former colony reached a deal in October to hand back the Indian Ocean isles -- which it kept control of after Mauritius gained independence in the 1960s -- on condition that a UK-US military base remains on the largest island, Diego Garcia.

But after Navin Ramgoolam became prime minister in November, he reopened talks, reportedly seeking greater financial compensation and to renegotiate the length of the base's proposed lease.

"We have reached an agreement ready to be signed with Great Britain concerning Chagos," Ramgoolam told parliament on Tuesday.

The prime minister said the vital question of Mauritius's "unambiguous, undiluted" sovereignty over the entire archipelago, including Diego Garcia, "has been taken into account in the new deal".

He did not give further details.

But he said a possible extension of the 99-year lease on the military base would be "discussed by both parties".

The UK government played down the notion that a deal had been struck.

"Once an agreement is reached, further details of the treaty will be put before both Houses for scrutiny and treaty ratification in the usual way," a spokesman for Prime Minister Keir Starmer told reporters.

He repeated that Britain would consult US President Donald Trump's new government after the deal was criticised by some of Trump's Republican allies.

"Clearly there is a new US administration in place and as we have previously said it is absolutely right that it has the chance to consider the agreement in full," the spokesman added.

Ramgoolam has said Mauritius would also have to wait for an opinion from Trump's administration.

"Let him see whether the deal is good or bad," Ramgoolam said in parliament.

"The president has just taken office... He has his own priorities. I'm not in a position to impose a timetable on him," Ramgoolam said.

Britain set up the Diego Garcia base after independence and leased it to the United States, which has used it as a hub for long-range bombers and ships, notably during the wars in Afghanistan and Iraq.

But in doing so, Britain evicted thousands of Chagos islanders who have since mounted a series of legal claims for compensation in British courts.

Under the previously proposed agreement, the UK would retain a 99-year lease on the base for a payment of A?90 million ($110 million) a year, according to British media.

If Washington refuses to support the deal, Ramgoolam said Mauritius would pursue its fight for full sovereignty over the Chagos islands.

(AFP)

An undated file photo shows Diego Garcia, the largest island in the Chagos archipelago and site of a major United States military base in the middle of the Indian Ocean leased from Britain in 1966. (Reuters)

Mauritius says 'new deal' reached with UK on Chagos Islands