Argentina has accused the UK of deploying nuclear weapons near the Falklands.
Foreign minister Hector Timerman made the claim as he urged the United Nations to intervene in the long-running dispute over the islands.
He said Buenos Aires had intelligence that a Vanguard submarine had been deployed in the area.
"Thus far the UK refuses to say whether it is true or not," Mr Timerman told a press conference in New York through a translator. "Are there nuclear weapons or are there not?
"The information Argentina has is that there are these nuclear weapons."
Mr Timerman accused Britain of using an "unjustified defence of self-determination" to maintain a military base on the Falklands, which allowed her to dominate the Atlantic.
"It is perhaps the last refuge of a declining empire," he insisted. "It is perhaps the last ocean that is controlled by the UK."
He said Britain had been "colonialist throughout (her) history", and should now "give peace a chance".
Earlier, UN Secretary General Ban Ki-moon issued a statement expressing "concern about the increasingly strong exchanges" between the two governments.
After holding talks with Mr Timerman, he said the international body would be happy to help mediate the dispute if asked.
UK 
