This is including a United States (US) British military base, with London hoping for sign-off before Donald Trump's inauguration.

Britain struck a deal in October to hand over control of the Chagos Islands to Mauritius while retaining control of the military base on Diego Garcia, the largest island of the Chagos Archipelago in the Indian Ocean, under a 99-year lease - an agreement that needs to be ratified.

Since then, an ally of US President-elect Donald Trump and new Mauritian Prime Minister Navin Ramgoolam have publicly criticised the deal.

Ramgoolam said last month his government wanted to renegotiate the deal. Britain has said the deal works for all sides.

British media have reported that London has offered to frontload a tranche of payments to Mauritius for the lease of the strategically important military base.

A UK-Mauritius joint statement provided by the British government on Monday reiterated London's position that good progress had been made and discussions were ongoing to reach an agreement that was in both sides' interests. It offered no new details.

"Both countries reiterated their commitment to concluding a treaty providing that Mauritius is sovereign over the Chagos Archipelago; and that would ensure the long-term, secure and effective operation of the base on Diego Garcia," it said.

Trump takes office on January 20. Marco Rubio, his pick as Secretary of State, has said the deal poses a threat to US security by ceding the archipelago, with its base used by US long-range bombers and warships - to a country allied with China.

Some Chagossians have also criticised the negotiations, saying they cannot endorse an agreement they were not involved in and have said they will protest against it.

Reacting to Monday's joint statement, community organisation Chagossian Voices said it believed "exclusion from the talks constitutes a flagrant abuse of our human rights".

--Reuters--