The 193 United Nations member states on Wednesday voted overwhelmingly to demand the UK over control of the Chagos islands to Mauritius "as soon as possible".
Total of 116 countries voted in favor of a non-binding resolution presented by African countries who urged Britain to "withdraw its colonial administration" from the Chagos Islands within six months.
Only six countries, including Britain and the United States, voted against the measure while 56 others abstained, including Canada, France and Germany.
The Indian Ocean archipelago has been at the center of a decades-long dispute over Britain's decision to separate it from Mauritius in 1
In February, the International Court of Justice handed Mauritius a victory when it said in a legal opinion that Britain had illegally split the islands and should give up
Mauritius argues the Chagos archipelago was part of its territory since at least the 18th century and was taken unlawfully by The UK in 1965, three years before the independence of the nation.
However, Britain insists it has sovereignty over the archipelago, which it calls the British Indian Ocean Territory.
Wednesday's vote was the second time in two years that Britain had to defend its ownership of the United Nations.
In 2017, only 15 countries including Britain and the US voted to oppose a request for the ICJ ruling.
Before the vote, Britain and the US wrote to all UN missions, urging them to oppose the draft resolution, arguing the fate of the Chagos is a bilateral issue.
"This is not a matter of decolonization for the General Assembly," British Ambassador Karen Pierce wrote. "It is a bilateral sovereignty dispute between the United Kingdom and Mauritius."
US acting Ambassador Jonathan Cohen argued the court opinion was non-binding and was in no way a legal ruling that decided on the dispute.
In 2016 , Britain renewed a lease agreement with the US for the use of Diego Garcia until 2036.