Argentinian President Javier Milei has demanded that Britain cease oil exploration near the disputed Falkland Islands, threatening legal action if London fails to comply.

Buenos Aires maintains that the South Atlantic archipelago, which it calls the Malvinas, is part of its territory, despite it being administered by the UK since 1833.

The two countries fought a brief war over the territory in 1982 after Argentine forces seized the islands and Britain sent a naval task force to retake them. In a 2013 referendum, Falkland Islanders overwhelmingly voted to remain a British overseas territory, a vote Buenos Aires does not recognize as resolving the sovereignty dispute.

Milei said in a post on X on Monday that he had given instructions to the Foreign Ministry and legal experts “to initiate international arbitration against the UK for the illegal plundering of our resources through the Sea Lion Project.”

“If in 2 weeks the UK does not halt the illegitimate exploitation, we will go to the International Tribunal for the Law of the Sea (ITLOS),” he warned.

The Sea Lion oil field lies around 220 km (137 miles) north of the Falkland Islands and is estimated to hold around 1.7 billion barrels of oil. British company Rockhopper and Israeli firm Navitas, which are developing the $2.2 billion project, are planning to begin drilling on site in early 2028.

ITLOS is an independent court established under the 1982 UN Convention on the Law of the Sea. Decisions by the Hamburg-based tribunal are legally binding, although it lacks the means to make countries comply with them.

The British government has said it fully supports the companies involved in the Sea Lion project, insisting that the people of the Falklands have the “right to develop their natural resources as they see fit.” Rockhopper and Navitas also previously shrugged off Argentina’s complaints about the project, arguing that they are operating under a valid license issued by the UK.

Earlier in September, Buenos Aires initiated sanctions proceedings against 60 people and companies ‌over being involved in oil exploration near the Falklands.

The Argentinean government has doubled down on its claim to the islands after US President Donald Trump, who previously called Milei his “favorite president,” said in late August that Washington’s longstanding neutral stance on the status of the Falklands was under review.

Milei dedicated most of his speech at the UN General Assembly in New York last week to the Falklands, saying that Argentina could “take matters into our own hands” if the global body fails to act against the Sea Lion Project.

UK Defense Secretary Wes Streeting responded by accusing the Argentinean leader of reciting the “same old bogus propaganda” and insisting that Britain has “the ability to defend” the Falklands militarily.