Legal proceedings have been launched by Argentina against 45 individuals and companies in a fresh move to enforce a crackdown on oil exploration around the Falkland Islands.
The office of president Javier Milei announced the measures on Saturday morning via a post on X, coming a day after he pledged firmer action against businesses operating in the British overseas territory and reasserted his nation's territorial claim.
According to the Argentinian government, legal actions could also target shareholders and service providers linked to the firms involved in the energy projects.
Officials did not name the specific individuals or businesses facing proceedings.
In a national address delivered on Friday, Mr Milei reiterated his country's claim over the archipelago and stated he would enforce sanctions on any energy companies operating in the area.
The renewed friction surrounding the British overseas territory follows remarks from US president Donald Trump indicating that Washington would not assist the UK in any future conflict over the Falklands.
Responding to Mr Milei’s speech, Foreign Secretary Ed Miliband wrote on X: "The UK’s position on the Falkland Islands is unwavering.
"The Islands are British and will remain so because that is the overwhelming position of the Islanders.
"Their right of self-determination is paramount, grounded in international law and we will resolutely uphold it."
Defence Secretary Wes Streeting stated that Britain's commitment to the Falklands remains "absolute and unshakeable".
Downing Street indicated that there would be no formal diplomatic response from the UK to the threats made by Mr Milei, as London seeks to strengthen relations with Buenos Aires.
In a 2013 referendum on sovereignty, Falkland Islanders voted overwhelmingly to remain a British overseas territory, with 99.8% backing the status quo and only three votes cast against.
Although Washington maintains formal neutrality, the US provided critical support for the British campaign to retake the archipelago following the 1982 invasion by Argentinian forces.
That invasion triggered the Falklands War, which resulted in 255 British military deaths across just over 70 bloody days, alongside the deaths of 655 Argentinians and three Falkland Islanders.
During his address, Mr Milei said: "Our role and relevance as a country in the world has changed dramatically.
"The Falklands are our future – we need to recover these islands which are nationally relevant. There is no other path forward."
He confirmed plans to sign executive decrees implementing sanctions against any commercial entities involved in offshore oil production in the region.
Furthermore, he labeled the Sea Lion oilfield—a project jointly owned by a British and an Israeli firm, with production anticipated to start in 2028—a "clear and present danger" to Argentina's claims.
"If we do not act swiftly in a few months, they will have the material capacity to access the oil that lies underneath our sea. Something that has never happened before," he said.
UK-based exploration company Rockhopper, which is developing the oilfield alongside Navitas near the islands, stated that it did not expect the measures by the Argentinian government to have a "material effect" on the initiative.
A spokeswoman for No 10 reiterated that the UK fully supports the right of the Falkland Islanders to develop their natural resources for their own economic benefit, adding that "this is an integral part of their right to self-determination".
The Argentinian leader also outlined intentions to enhance national defence infrastructure by establishing a new naval base in Tierra del Fuego in the south of the country.
Mr Milei asserted that the US was currently "assessing their historical position in regard to the Falklands".
When questioned about whether a diplomatic reply would follow the threats, the Downing Street spokeswoman stated that the UK continues "to have a diplomatic relationship with Argentina, and from our perspective we want to continue to strengthen that".
On Thursday, the US president implied he would not support the UK in a dispute over the archipelago, citing the lack of British assistance for his military campaign in Iran.
No 10 declined to address the remarks made by Mr Trump, stating that they were "a matter for the US president".
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