Argentine President Javier Milei escalated his country's long-standing sovereignty claim over the Falkland Islands on Thursday by vowing economic sanctions against companies developing an offshore oil project near the British-controlled territory.

In a televised national address, Milei cited recent comments from U.S. President Donald Trump suggesting Washington might reconsider its neutral stance on the dispute. He described the planned development of the Sea Lion oilfield as a "clear and present danger" that Argentina could not ignore.

The project involves Britain's Rockhopper Exploration and Israel's Navitas Petroleum, with drilling expected to begin soon and production targeted for 2028. Milei announced a decree to accelerate sanctions already authorized under Argentine law and pledged to send Congress an urgent bill to broaden penalties to include suppliers and other participants.

Milei also directed increased funding to the Defense Ministry for construction of a naval base in Tierra del Fuego. He framed the move as strengthening Argentina's position as a logistics hub in the South Atlantic and supporting its Antarctic interests.

"The Malvinas are Argentine by history and by right," Milei said. "There is no debate about that." He added that the United Kingdom faces multiple crises and is on a path of decline, while Argentina's future is flourishing.

The announcements come amid ongoing tensions over resource extraction in waters Argentina claims as its own. Britain maintains that the islanders have the right to self-determination and choose to remain British.

Milei positioned his actions as necessary to prevent unauthorized exploitation of resources, referencing a United Nations resolution that calls on both sides to avoid unilateral measures. Oil company Rockhopper stated it does not expect the developments to have a material effect on the project timeline.

The speech highlighted Milei's alignment with Trump on foreign policy matters, presenting the potential U.S. policy shift as recognition of Argentina's value as a reliable partner aligned with Western values.