Tension between Britain and Argentina over the Falkland Islands prompted an awkward exchange between president Cristina Fernandez and prime minister David Cameron at the G20 summit last night.
Ms Fernandez has launched a wide-ranging diplomatic offensive to assert Argentina's claims to the British-ruled islands 30 years after the Falklands war.
She has accused London of maintaining "colonial enclaves" and demanded sovereignty talks.
Mr Cameron approached Ms Fernandez in Mexico to thank her for supporting proposed European banking reforms and then, according to her spokesman, he raised the issue of the Falklands.
Ms Fernandez responded by offering him an envelope, which she had among her papers, containing several dozen United Nations resolutions calling for dialogue over the South Atlantic islands.
"He answered that he wasn't going to talk about sovereignty to which (Fernandez) responded that she also didn't want to discuss sovereignty and just wanted to talk as the UN resolutions demand," Ms Fernandez's spokesman said.
Mr Cameron "refused to receive the envelope and he walked away," the spokesman told Argentine television from the summit.
In London, a Downing Street spokeswoman said Mr Cameron had sought out the president and told her: "I'm not proposing a full discussion now on the Falklands but I hope you have noted that they are holding a referendum and you should respect their views. We should believe in self-determination and act as democrats here in the G20."
A British source said Ms Fernandez did have a document with her, but it was not clear whether she was trying to hand it to Mr Cameron or get it filmed on camera.
The Argentine delegation had a hand-held camera with them, the source said.
Britain has dismissed Argentina's calls for sovereignty talks, pointing out that the Falklands are self-governing and that talks could only take place if the islanders wanted them.
The islands' 3,000 inhabitants are planning a referendum on whether they want to stay part of Britain's self-governing overseas territories, a step designed to outflank Argentina's sovereignty claims.