The legal case seeking to halt the illegal Sea Lion oil development gained significant institutional support on Friday. The Municipality of Río Grande formally appeared before the Federal Court of First Instance in case file FCR 13706/2026 , requesting its intervention as an "interested party" (third-party intervenor) and expressly endorsing the lawsuit and the precautionary measure promoted by the Malvinas Islands Ex-Combatants Center of La Plata (CECIM) and the Argentine Association of Environmental Lawyers (AAdeAA) .

The legal document, digitally signed at 12:06 pm by the attorney and community legal advisor, Dr. Sebastián Tesei, along with the sponsors Maximiliano Pérez Arias and Mariela Sambad, expresses categorical support for the preventive action for collective environmental damage against Rockhopper Exploration and Navitas Petroleum .

The municipal filing comes just 48 hours after Judge Mariel Borruto declared the full competence of the court and the international jurisdiction of the Republic of Argentina, having notified the Tierra del Fuego State Prosecutor's Office. With this step, Mayor Martín Pérez is taking the political and procedural initiative at the provincial level, distinguishing himself from the passivity thus far shown by the administration of Gustavo Melella.

The coastal municipality and the preventive protection of the Argentine Sea

In establishing the grounds for its intervention under Article 90, paragraph 1, of the National Civil and Commercial Procedural Code (CPCCN), the city demonstrated a specific, concrete, and distinct legal interest with respect to the diffuse general interest:

Full support for halting construction and federal reserve

In its petition, the government of Río Grande expressly requested Judge Borruto to issue an ex parte injunction ordering Rockhopper and Navitas to refrain from initiating or continuing drilling, laying submarine pipelines, anchoring floating production, storage and offloading ( FPSO ) units, and all extractive activities. It also reserved the right to appeal the case to the Supreme Court of Justice of the Nation, pursuant to Article 14 of Law 48.

The appearance of Río Grande strengthens the collective standing of the lawsuit. While oil companies try to stem the collapse of their shares in London and Tel Aviv, the main industrial and coastal city of Tierra del Fuego formalizes its position in the courts: the clandestine exploitation of oil in the Malvina Islands not only violates indivisible territorial sovereignty, but also represents an imminent ecological threat to the coasts of Tierra del Fuego and Patagonia.

THE FULL TEXT OF THE LEGAL PRESENTATION OF THE MUNICIPALITY OF RIO GRANDA