Argentina has formally asked United Nations Secretary General Ban Ki-moon to bring the UK into talks about the sovereignty of the Falkland Islands following a row over drilling rights in the region.
Argentine Foreign Minister Jorge Taiana said he had asked Ban to help stop "further unilateral acts" by the UK, referring to the UK's decision to begin oil drilling under a seabed off the islands.
The UK government says the islands have a "legitimate right" to develop an oil industry within their waters, reports the BBC.
Last week it was revealed that the UK and the Falkland Islands ignored Argentinian efforts to stop oil and gas exploration in UK-controlled waters in the south Atlantic.
Drilling activity has now started using the Ocean Guardian rig, 100 miles offshore. Geological surveys suggest up to 60 billion barrels may lie beneath the seabed.
Argentina and the UK went to war over the islands in 1982. The current Argentine government has ruled out any military action over the islands, but is stepping up a diplomatic offensive to try to pressure London into negotiations.