Argentina last night intensified its diplomatic offensive against Britain's oil exploration off the Falkland Islands by taking the case to the United Nations.
The Argentinian foreign minister, Jorge Taiana, spelled out Buenos Aires's demands in a meeting in New York with the UN secretary general, Ban Ki-moon, just a day after mobilising Latin American and Caribbean support.
Taiana told reporters afterwards that Ban was not happy that tensions had worsened because of Britain's decision to start drilling and was willing to continue his "good offices" mission.
The minister said the meeting was "very cordial, positive" but did not say if Ban had agreed to pressure London over the islands' sovereignty. The secretary general made no immediate comment.
Argentina has demanded an immediate cessation of the British drilling for oil and gas that started this week, terming it "the latest illegitimate and unilateral actions by the UK". The next step would be to table a resolution at the UN general assembly.
The UN has called for talks between Britain and Argentina but has little power to intervene without the backing of the security council, where the UK would be able to veto substantive resolutions.
Brazil's president, Luiz Inácio Lula da Silva, added pressure by saying the council was an anachronism tilted in favour of western powers. He said: "It is not possible that Argentina is not the owner while England is, despite being 14,000km away."
He also repeated long-standing complaints that Brazil and other emerging powers should be included as permanent members of the security council.
British officials have privately admitted frustration, but no great surprise, that mainstream Latin leaders have thrown their weight behind Buenos Aires.
After the Argentinian minister's meeting with the UN secretary-general, Sir Mark Lyall Grant, the UK's permanent representative to the UN, reiterated British claims to sovereignty over the Falkland islands, South Georgia and the Sandwich Islands.
"This position is underpinned by the principle of self-determination as set out in the UN Charter. We are also clear that the Falkland Islands government is entitled to develop a hydrocarbons industry within its waters, and we support this legitimate business in Falklands' territory." In a statement yesterday Downing Street said drilling would continue.
With Argentina's regional allies lining up to denounce London, the Obama administration, which wants to improve US ties with Latin America without alienating Britain, sought to distance itself from the row.
"I think we are neutral on the question of sovereignty. We do recognise the current UK administration of the islands," said Philip Crowley, of the US state department, before urging "good-faith dialogue" between Buenos Aires and London.
The sovereignty standoff flared this month over the arrival of a rig, the Ocean Guardian, which is to drill offshore for oil and gas deposits.
Buenos Aires scored a diplomatic victory on Monday when it turned a summit of 32 countries in Mexico into a platform to accuse Britain of flouting international law by permitting drilling.
Argentina presented a statement quoting the Mexican president, Felipe Calderón, as saying that "the heads of state represented here reaffirm their support for the legitimate rights of the republic of Argentina in the sovereignty dispute with Great Britain."
The Argentinian president, Cristina Kirchner, ruled out any plans to try to keep the British boats or rigs out.
"We do not believe in methods like blockades," she told reporters. But in her speech at the summit she reiterated Argentina's claim to the islands and blamed the Foreign Office for fanning tensions.
She said: "When in these last few days England decided to install an oil rig offshore and Argentina – in exercise of its domestic law – made decisions as a sovereign state, the Foreign Office floated the idea of a potential war threat by Argentina."