Russia has accused the United States of "unlawful actions" after US forces seized the Russian-flagged oil tanker Marinera in international waters on January 7. Moscow says the seizure breaches international maritime law and risks escalating already tense Russia–US relations. Russian Foreign Minister Sergey Lavrov demanded that Washington respect maritime law and stop actions against the Marinera and other civilian ships at sea. The Russian Foreign Ministry stated, "Alongside the US administration's disregard for the accepted norms of international maritime navigation, Washington's readiness to provoke acute international crises, including in Russian-American relations, which are already severely strained, is both regrettable and alarming." The ministry warned the incident "can only lead to a further escalation of military-political tensions in the Euro-Atlantic region and a dangerous lowering of the threshold for using force against civilian shipping." Russia also accused the United Kingdom of aiding the US military operation in North Atlantic waters. Russia said the tanker had been temporarily authorized to sail under the Russian flag since December 24 and was peacefully passing through international waters en route to a Russian port. It stressed that US authorities had been informed about the ship’s legal civilian status. According to international law cited by Russia, only the flag state has jurisdiction over vessels on the high seas. Boarding or seizing ships without permission is only allowed under narrow reasons like piracy or slave trading, which do not apply here. Russia said it refused US consent and formally protested over the US Coast Guard's pursuit of the vessel for weeks. The ministry called the seizure a "gross violation of fundamental principles and norms of international maritime law and the freedom of navigation." Concerns were raised about crew safety and environmental risks, especially since the seizure happened during severe weather. Rejecting US sanctions as a legal reason, Russia condemned claims that the operation serves US ambitions over Venezuela’s oil resources, calling them "profoundly cynical." On social media platform X, Russia demanded: "We call on Washington to immediately cease its unlawful actions against the Marinera and other vessels engaged in lawful activities on the high seas." Russia’s Transport Ministry similarly denounced the US use of force against a legally registered ship. The tanker had been pursued by the US Coast Guard after being sanctioned for involvement in illicit oil transport related to Iran and Venezuela. When US authorities tried to seize it under the Guyana flag last month, the crew refused and changed course. The ship was later renamed Marinera and re-registered under Russia. The final seizure occurred about 190 miles south of Iceland. The US said the operation was done under a federal court order for sanctions violations with help from UK defence forces.