Argentina will take legal action against any companies involved in oil exploration off the disputed Falkland Islands as part of a drive to pressure Britain into sovereignty talks, the foreign minister said.
"With these actions we assume the responsibility of defending Argentina's natural resources," Foreign Minister Hector Timerman told a news conference on Thursday.
"The South Atlantic's oil and gas are property of the Argentine people."
Three decades after it repelled an Argentine invasion of the Falklands, Britain has vowed to defend the archipelago, saying it will negotiate sovereignty or oil rights only in the unlikely event that the 3,000 islanders want that.
The conflict has heated up in recent months as the war's 30-year anniversary nears and findings by British exploration firms raise hopes of a potential tax windfall and boon to the islands' economy.
Argentina says the exploration and drilling activities are illegal since the area is contested. It says Britain is violating Argentine law and UN resolutions that call for talks and prohibit unilateral action as long as the dispute persists.
The South American country, run by center-left President Cristina Fernandez, will bring civil and criminal charges to sanction the gamut of companies involved.
Britain reacted by saying it supported the rights of Falkland islanders to exploit their oil reserves. This was an "integral part of the right of self-determination", a British Foreign Office spokesman said.
It was not immediately clear what kind of judicial action Argentina could take. The government said it planned to seek international cooperation to gather information or enforce court orders issued by Argentine authorities.
Several companies have drilled in waters off the islands, which are called Las Malvinas in Spanish. British explorer Rockhopper has been seeking a partner to invest in the $2 billion Sea Lion project.
Borders & Southern and Falkland Oil & Gas are set to drill wells south of the islands this year.
An industry source in London said legal action against companies involved in Falklands oil exploration "will have no impact on Rockhopper's operations as they look to develop the Sea Lion project."
Borders & Southern declined to comment.