It is not yet clear how or to what extent the sanctions will be imposed or tightened. In Argentina, a current law already allows for restrictions of activities of oil companies participating in projects considered unauthorised on the islands.
Two oil companies – Britain’s Rockhopper Exploration and Israel’s Navitas Petroleum – are due to begin extracting oil in the Sea Lion oilfield off the Falklands coast within two years, something Milei said Argentina could not allow.
A joint statement from the two firms on Friday said it had the valid licences granted by the government of the Falkland Islands, “and with the full support of the UK government.”
The project is due to deliver its first oil in 2028, Rockhopper and Navitas said the partnerships’ timetable would not be affected.
The Sea Lion oilfield, around 130 miles from the islands, contains an estimated 1.7 billion barrels of oil – described by Rockhopper as a field containing “highly marketable crude”.
Milei also announced plans for a naval base in Tierra del Fuego in the south of Argentina, saying Trump and the US were “assessing their historical position in regard to the Falklands”, which Argentina refers to as Las Malvinas.
“That is not empty words as they understand that Argentina is a reliable partner and a valuable ally for decades to come,” he said, describing the UK as a nation “in decline”.
On Thursday, President Trump hinted the US would not help the UK in any future Falklands conflict because Britain “had not been there to help me” during his war with Iran.
Trump’s latest remarks on the islands come after he previously said the US position on the Falklands is one of many under review.
On Friday, Foreign Secretary Ed Miliband said the UK would “resolutely uphold” the self-determination of the islands.
Writing on X on Friday, Miliband said the Islands would remain British as that is the “overwhelming position of the islanders.”
Defence Secretary Wes Streeting also said Britain’s commitment to the Falkland Islands was “absolute and unshakeable”.
“Milei’s statement overnight tells us more about domestic politics in Argentina than it does about the Falkland Islands,” he wrote in his own post on X.
In an earlier statement, Downing Street said it was “not the first time” the Argentine government had made economic threats against the Falkland Islands.
“We are clear that the Falkland Islanders’ right of self-determination extends to the right to exploit their own natural resources,” it said.
Conservative Party leader Kemi Badenoch said “Britain does not surrender to bullies”.
“If (Milei) wants a stronger Argentina, he should build its economy, not threaten others.”
Although the US is formally neutral, Washington provided support for Britain’s campaign to retake the islands after the Argentinian invasion in 1982.
Argentine forces landed on the Falklands to stake a territorial claim in 1982, sparking a 74-day war over the territory as a British military task force ejected them.
The conflict led to the deaths of 255 British military personnel, three islanders and 649 Argentine military personnel.
In a sign of the ongoing tensions between the two countries over the issue, Argentina players celebrated their victory over England in the World Cup by waving a banner in support of their country’s territorial claim.