The Argentine government described exploration activity by British oil and natural gas explorers as "illegal and clandestine," reports British newspaper The Daily Telegraph.
Argentina is at odds with the British government over claims to the Falkland Islands. Buenos Aires maintains the islands are left over from the British colonial area and should fall under Argentine rule.
Argentina invaded Falkland Islands in 1982.
Argentine President Cristina Fernandez de Kirchner said British oil companies were operating "in a sovereign area" and not authorized to do so under national law.
London said Buenos Aires was working to scupper the economic livelihood of the islands.
"Hydrocarbon exploration in the Falklands is a legitimate commercial venture," the newspaper quoted the British government as saying. "We are studying Argentina's remarks carefully and will work closely with any company potentially affected to ensure that the practical implications for them are as few as possible."
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