Britain and Mauritius announced on Monday that they are making significant strides in negotiations aimed at finalizing a treaty concerning the future of the Chagos Islands, which includes the U.S.-British military installation at Diego Garcia.

In October, Britain reached an agreement to transfer control of the Chagos Islands to Mauritius while retaining authority over the strategically vital Diego Garcia base; however, a formal treaty has yet to be established.

Since that time, both a supporter of U.S. President-elect Donald Trump and the newly appointed Prime Minister of Mauritius, Navin Ramgoolam, have openly criticized the arrangement. Last month, Ramgoolam expressed his government’s desire to renegotiate the terms, but Britain has asserted that the current deal is beneficial for all parties involved.

A joint statement from the UK and Mauritius, released by the British government on Monday, emphasized that “good progress” has been made and that discussions are ongoing to reach a mutually beneficial agreement.

The statement confirmed that both nations are committed to finalizing a treaty that recognizes Mauritius’s sovereignty over the Chagos Archipelago while ensuring the long-term, secure, and effective operation of the Diego Garcia base. There are concerns that U.S. President-elect Donald Trump may reconsider the agreement upon taking office in January, particularly due to U.S. apprehensions that the British transfer of the islands to Mauritius could compromise security in light of China’s growing influence in the region.