The U.S. said Wednesday that in its attempt to blockade sanctioned oil exports from Venezuela, it seized two tanker ships, one of which was newly registered under the Russian flag.
In a post on X, the U.S. European Command said the tanker — which it called Bella 1, the ship's former name — had been seized in the North Atlantic for violations of U.S. sanctions on Venezuelan oil.
The ship, now named Marinera, is just one that Russia has reflagged to join its "dark" fleet.
"This has moved beyond a sanctions case into a real-time jurisdictional challenge, where the key question is what legal basis exists for enforcement on the high seas," Dimitris Ampatzidis, senior risk and compliance analyst at energy consulting firm Kpler, told CNBC. "The vessel's identity and history remain constant, but its flag status can significantly raise the diplomatic stakes."
According to maritime lawyers who spoke with CNBC, a vessel is essentially considered a floating island of the country whose flag it bears.
Automatic Identification System tracking data by Kpler shows the path of the vessel and the diversion the vessel made.
Kpler's AIS data — real-time location information transmitted by ships — shows that the tanker recently made a sharp turn in the Atlantic Ocean near Scotland.
More than two weeks before the ship was seized, the U.S. stopped and attempted to board the tanker, which was registered as the Bella 1 under a fraudulent Guyana flag, during the ship's transit to Venezuela to be filled with the sanctioned crude.
On Dec. 31, Russia notified the U.S. that the ship had changed its name to Marinera and switched its registration to Russia, according to Lloyd's List. The vessel left the Caribbean.
Another newly Russian-flagged tanker linked to moving Venezuelan oil, the Premier, which was reflagged from Gambia to Russia on Dec. 22, remains empty outside the Jose terminal in Venezuela, according to Lloyd's List vessel tracking.
In a separate X post Wednesday, U.S. Southcom announced that the Panama-flagged tanker Sophia had been seized and was being escorted to the U.S. by the U.S. Coast Guard.
The Sophia is laden with around 2 million barrels of crude oil that was loaded at Jose Oil Terminal in Venezuela around Dec. 26-29, as confirmed by satellite imagery and port reports seen by Kpler, Emmanuel Belostrino, senior manager of crude oil market data at Kpler, told CNBC.
The tanker's previous voyage was also from Venezuela, when it similarly loaded around 2 million barrels of crude in early August 2025 before heading to offshore Malaysia, Belostrino said.
"The sanctioned cargo was likely transferred to another vessel via dark ship-to-ship transfer, but Kpler has not determined the partner vessel," he said.
Kpler analysis shows Sophia's involvement in sanctioned trade may extend back to November 2021. In addition to transporting sanctioned Venezuelan crude, the vessel has been linked to transporting sanctioned Iranian and Russian oil to China, according to Kpler.
The seizure of the Sophia comes after the Dec. 27 seizure of the Panama-flagged ship Centuries. Maritime experts have told CNBC these seizures may have been conducted under the 2002 Salas-Becker agreement, which allows U.S. authorities to board Panamanian-flagged vessels with just two hours' notice.
