In a social media post, President Javier Milei gave British and Israeli companies behind the Sea Lion project two weeks to end operations, warning that otherwise he had "instructed the Foreign Ministry and legal teams to initiate international arbitration" against the UK over what he called "the illegal plundering of our resources through the Sea Lion Project".
Milei said that if the "illegitimate exploitation" of the region did not end within two weeks, Argentina would take the matter before the International Tribunal for the Law of the Sea, an independent judicial body based in Hamburg responsible for applying the United Nations Convention on the Law of the Sea.
The companies involved insist they hold valid licences issued by Britain.
The comments heighten tensions between the UK and Argentina over sovereignty of the archipelago, known in Argentina as Las Malvinas, more than 40 years after a British military task force ejected Argentine forces that invaded the territory in 1982.
The move follows Milei's criticism of the UN in his speech at the General Assembly, where he said the organisation had become "a useless organisation" serving "arrogant parasites dressed up as well-intentioned bureaucrats" for failing to act over the islands' sovereignty.
Responding to the escalating rhetoric, UK Defence Secretary Wes Streeting said that Argentina "lacks the ability" to seize the Falklands by force.