Britain has strongly rejected a demand by Argentina to begin negotiations on the handing over of the Falkland Islands.
The reaction came after Argentine president Cristina Fernandez de Kirchner asked Britain to return the islands.
A spokesperson for the Falklands Islands government on Thursday said: "We are not a colony - our relationship with the United Kingdom is by choice".
It has already been announced that a referendum on sovereignty will be held in March this year, but the diplomatic tension has been raised by Ms de Kirchner in her open letter to Britain's Prime Minister David Cameron, the BBC reports.
She said that in 1833, Argentina had been forcibly stripped of the Malvinas, as the islands are known in Argentina, and this was a blatant exercise of 19th century colonialism.
Earlier, Downing Street said Mr Cameron would "do everything to protect the interests of the Falklands islanders."
A spokeserson for the Prime Minister says the people of the Falklands have shown a clear desire to remain British.