(Refiles to fix dateline)
LONDON, Sept 21 (Reuters) - British Prime Minister Andy Burnham spoke with his Mauritian counterpart, Navin Ramgoolam, on Monday, pledging to work towards a resolution over the disputed status of a U.S.-British military base on the Indian Ocean island of Diego Garcia.
Britain last year agreed a deal to cede sovereignty of the Chagos Islands to Mauritius after more than two centuries of control, while retaining a 99-year lease over its biggest island, Diego Garcia, and its strategic military base.
But the legislation required to implement the agreement was paused because of opposition from the United States with U.S. President Donald Trump describing the deal earlier this year as a "big mistake".
"The prime minister underlined his commitment to working with Mauritius and the United States on a way forward that secures the operation of the base and protects UK national security," according to a readout of the call from Downing Street.
The leaders agreed to stay in close contact and said their foreign ministers should meet at the U.N. General Assembly in New York this week, the statement said.
While Britain has already signed the treaty with Mauritius, the bill needed to enact the handover has yet to complete its passage through the British parliament.
Under the deal negotiated by Burnham's predecessor, Britain would retain control of the strategically important Diego Garcia base for almost a century, preserving military operations there.
(Reporting by Andrew MacAskill; Editing by Kate Holton)
