A British firm is expected to start drilling for oil near the Falkland Islands today, despite strong opposition from Argentina.
The move is stirring tensions between London and Buenos Aires, who fought a war over the territory in 1982.
The tiny Falkland Islands, located 450 kilometers off the eastern coast of Argentina, have been held by Britain since 1833. But they are also claimed by Argentina, where they're known as the Malvinas.
Argentina unsuccessfully invaded the islands in 1982, leading to a brief but bloody war that left more than 900 dead.
While Argentina has ruled out another invasion, it is working against the British venture.
Last week, Argentine President Cristina Kirchner signed a decree ordering any ship passing through Argentine waters to request permission before going to the islands -- potentially slowing oil exploration.
Kirchner is scheduled to speak today at a summit of 25 Latin and Caribbean leaders known as the Rio Group.
She is expected to urge regional leaders to condemn British oil exploration in the Falklands.
The Rio Group in the past has backed Argentina's territorial claim.
Venezuela has already offered its support. President Hugo Chavez, addressing Britain's Queen Elizabeth on his weekly television show on February 21 , said, "the English continue to threaten Argentina. Things have changed, Mrs. Queen. We're not in the year 1982 anymore. In the case of aggression against Argentina, be sure that the Argentine homeland is not alone, because it is our homeland too."
Argentina says Britain is evading UN resolutions calling for dialogue on the dispute.
Foreign Minister Jorge Taiana says Britain should "sit down and have a dialogue about sovereignty to overcome this anachronistic colonial situation."
Taiana is expected to meet UN chief Ban-Ki Moon on February 24 to encourage talks.
The British firm Desire Petroleum is looking to exploit some of the 60 billion barrels of crude that experts say may be found in the oil field near the islands.
That's as much as the North Sea crude reserves which contributed to 25 years of British prosperity.
Company spokesman David Willie told the BBC: "Desire is an oil company and it's exploring for oil and not getting involved in what Argentina is saying about going to the UN. The rig is sitting firmly inside [British] waters."
British Prime Minister Gordon Brown said on February 19 that he was "confident" diplomacy could resolve a standoff with Argentina.
Argentina says its offshore territories include not only the Falkland Islands but extend to the edge of the underwater continental shelf more than 2,000 kilometers away.
Earlier today, the website of the Falkland Islands' English-language newspaper, "Penguin News," was briefly hacked. Argentina's flag was posted on the site along with a Spanish-language article in support of Argentina's territorial claims.