Argentina has asked the United Nations to step into its dispute with Britain over the Falkland Islands but UN officials say mediation would need the agreement of London.
Argentine Foreign Minister Jorge Taiana put the request to UN Secretary-General Ban Ki-moon two days after the long-running dispute erupted again when a British company began oil exploration off the south Atlantic islands, which Argentina calls the Malvinas.
Argentina, which has claimed the islands since Britain established its rule in the 19th century, invaded them in 1982.
After a two-month war, it was forced to withdraw, but still claims the archipelago and says oil drilling by Britain's Desire Petroleum is a breach of sovereignty.
'We asked the secretary-general, in the exercise of his good offices, to transmit to the United Kingdom the need not to commit any more unilateral acts,' Mr Taiana said.
He said Britain should also comply with UN resolutions on 'the need to sit down and negotiate with Argentina on the Malvinas conflict'.
Britain has rejected Argentine objections to the oil exploration, saying the drilling is within international law.
Foreign Secretary David Miliband said: 'British sovereignty in respect of the Falklands is absolutely clear in international law.'
A UN General Assembly resolution entrusted the secretary-general months after the Falklands war with a 'good offices' mission to try to resolve the sovereignty dispute.
UN spokesman Ari Gaitanis said Mr Ban 'took note of Argentina's concerns' at the meeting with Mr Taiana and welcomed Buenos Aires' commitment to resolve the dispute peacefully.
He did not say whether Mr Ban would pass on Mr Taiana's message to Britain but said the UN chief 'reiterated that his good offices are available when requested by all parties in a dispute'.
Latin American leaders have said they will support Argentina's demands to stop drilling around the islands.
The Falklands are not an onshore oil producer and have no proven onshore reserves, but oil companies are betting that offshore fields hold billions of recoverable barrels of oil.