Twelve South American countries have issued a joint statement rejecting Britain's military presence in the British-controlled Falkland Islands.
The foreign ministers of the Union of South American Nations (UNASUR) also demanded a negotiated settlement to what they called an anachronistic colonial situation in the Americas.
The BBC reports tension over the islands has risen ahead of the 30th anniversary of the Falklands War next month.
Argentina foreign minister Hector Timmerman had threatened legal action against firms drilling off the UK territory, over which Argentina claims sovereignty.
But the UK Foreign Office said it was a legitimate commercial venture.
Prime Minister David Cameron said Britain would "continue to protect and defend" the islands.