Britain has confirmed it supported a US operation to seize the Russian‑flagged oil tanker Marinera (formerly Bella 1) in the North Atlantic on 7 January. The Ministry of Defence said RAF surveillance assets and the Royal Fleet Auxiliary’s RFA Tideforce provided assistance at Washington’s request, stressing that UK support was in full compliance with international law. ([lbc.co.uk](https://www.lbc.co.uk/article/russia-venezuela-trump-tanker-usa-5HjdQNC_2/))
US units intercepted the vessel after tracking it north‑east through waters between Iceland and Scotland. UK officials characterised the contribution as enabling support, including surveillance and a naval auxiliary, alongside basing arrangements for US aircraft. ([lbc.co.uk](https://www.lbc.co.uk/article/russia-venezuela-trump-tanker-usa-5HjdQNC_2/))
In its statement, the MoD said Marinera was assessed to have been involved in illegal activity linked to Hezbollah. Officials added the ship initially flew a false flag, switched off its AIS transponder while at sea, and sought to re‑flag while being pursued-behaviour associated by authorities with so‑called shadow fleet practices. ([standard.co.uk](https://www.standard.co.uk/news/politics/british-russian-john-healey-ministry-of-defence-bbc-radio-b1265399.html?utm_source=openai))
Defence Secretary John Healey said the action formed part of global efforts to tackle sanctions‑busting networks, describing the vessel’s history as “nefarious” and underlining the depth of UK–US defence cooperation. The department said the vessel had been sanctioned by the United States under its counter‑Iran sanctions regime. ([lbc.co.uk](https://www.lbc.co.uk/article/russia-venezuela-trump-tanker-usa-5HjdQNC_2/))
US authorities also announced a separate operation in the Caribbean against the tanker Sophia the same day. United States Southern Command described Sophia as a stateless, sanctioned “dark fleet” motor tanker now being escorted to the US by the Coast Guard. ([thenationalnews.com](https://www.thenationalnews.com/news/us/2026/01/07/us-seizing-venezuela-linked-oil-tanker-in-atlantic-after-weeks-long-pursuit/?utm_source=openai))
Moscow has disputed the legality of the North Atlantic seizure. Russia’s Transport Ministry said Marinera had only temporary permission to fly the Russian flag and argued that, under the 1982 UN Convention on the Law of the Sea, force may not be used against duly registered ships on the high seas. It also demanded humane treatment for the crew. ([themoscowtimes.com](https://www.themoscowtimes.com/2026/01/07/moscow-slams-us-use-of-force-against-russia-flagged-tanker-a91624?utm_source=openai))
International law places emphasis on a vessel’s nationality. Under Articles 91 and 92 of the UN Convention on the Law of the Sea, ships must sail under one flag and should not change it during a voyage except in cases of a genuine transfer of ownership or registry; a vessel using multiple flags “as convenient” may be treated as without nationality. That status can permit a limited right of visit on the high seas. ([un.org](https://www.un.org/depts/los/convention_agreements/texts/unclos/part7.htm?utm_source=openai))
AIS carriage and operation are required under the IMO’s SOLAS regime, with limited exceptions when security considerations apply. Authorities cite extended AIS dark activity, false flagging and mid‑voyage re‑flagging as red flags for deceptive shipping practices linked to sanctions evasion. ([imo.org](https://www.imo.org/en/ourwork/safety/pages/ais.aspx?utm_source=openai))
For shipowners, charterers and insurers, the episode reinforces due‑diligence priorities: verify flag status and recent changes, check AIS continuity, and scrutinise beneficial ownership and any designation history before providing services. UK partners have separately stepped up monitoring of the shadow fleet and undersea infrastructure in the North Atlantic through the Joint Expeditionary Force framework. ([gov.uk](https://www.gov.uk/government/news/joint-expeditionary-force-activates-uk-led-reaction-system-to-track-threats-to-undersea-infrastructure-and-monitor-russian-shadow-fleet?utm_source=openai))