Seven tankers made 14 trips from South Korea to Russia's Far East in July and August, carrying more than 176,000 metric tons of fuel, most of it diesel, the Guardian found in a 6 October analysis of port records and ship-tracking data. The UK and EU have sanctioned three of the ships, and one loaded its fuel from another tanker at sea off South Korea instead of at a terminal.

Ukrainian strikes have cut Russia's fuel output as Moscow scrambles for supplies, while fuel loaded at South Korean ports has flowed to Russia. Loadings began to surge in July, the same month South Korean President Lee Jae-myung pledged $100 million for Ukraine's reconstruction, the Guardian reported. That creates a tension in Seoul's policy toward the war: South Korea has provided Ukraine with humanitarian and non-lethal aid but ruled out sending weapons directly, while the fuel trade appears legal under South Korean law even though three of the tankers are under UK and EU sanctions.

Russia imported 368,000 metric tons of oil products by sea in August, 112,000 of them from South Korea, according to Kpler data analyzed by the Centre for Research on Energy and Clean Air (CREA) and cited by the Guardian. CREA's own August report gives 172,000 metric tons in total, including 18,000 from South Korea. Neither explains the gap.

Where the tankers said they were going

The Layla, a tanker under UK and EU sanctions, made two voyages from Ulsan to Vladivostok, carrying a total of 57,000 metric tons of diesel. It left South Korea on 19 July and 10 August. On the first trip, it told South Korean authorities it was bound for Vladivostok; on the second, it declared Niigata, Japan, but sailed to Vladivostok again.

The Astoria, a Russian-flagged tanker under UK, EU, and Australian sanctions, loaded nearly 11,000 metric tons of fuel at Ulsan on 1 August. It declared Japan as its destination but sailed to Vladivostok.

The Chongchon did not berth at a South Korean port. Instead, it took about 26,000 metric tons of fuel from the unsanctioned Celeste I at an anchorage off Yeosu in early August. It declared Singapore as its destination but headed to Vladivostok. The owners and managers of the four tankers did not respond to the Guardian's requests for comment.

Why Russia needs the fuel

Ukrainian drone strikes have severely disrupted Russia's refining capacity, the Guardian reported. In July, Ukraine's General Staff said the strikes had knocked out 42% of Russia's refining capacity, costing the industry billions of dollars.

Russian refinery throughput fell in June to its lowest level in more than 20 years, and diesel output is down nearly 30% from a year earlier, the International Energy Agency said, according to the Guardian.

Russia has also restricted fuel exports to protect domestic supplies, extending its diesel export ban until the end of October; on 2 October, Deputy Prime Minister Alexander Novak said Moscow could consider partially lifting the ban if there was overproduction, according to the Moscow Times.

Responses to the shipments

Seoul's non-lethal aid has included helmets, body armor, and demining vehicles, and in 2023 it pledged $2.3 billion in support, mostly in loans.

Isaac Levi, an analyst at CREA, told the Guardian:

"It is shocking that EU-sanctioned tankers loaded fuel at South Korean ports and carried it to Russia. This undermines the sanctions regime and South Korea's support for Ukraine."

South Korea's Foreign Ministry did not address the shipments or the sanctioned tankers. In a statement, it said the government supports international efforts to help end the war in Ukraine and bring about a peaceful recovery. The ministry said it was strictly enforcing its export controls and had expanded them to cover 1,402 non-strategic items with high potential for diversion to military use. The UK Foreign Office did not answer the Guardian's questions about UK-sanctioned tankers using South Korean ports, saying only that it remains committed to monitoring its sanctions.

Ties between Kyiv and Seoul are also strained over Ukraine's disclosure of its transfer of two North Korean prisoners of war to South Korea, which Seoul said should have remained private.

Operation MoLoChKa has now disabled 300 Russian shadow fleet ships in 11 weeks, SBS commander Robert "Madyar" Brovdi announced. The Unmanned Systems Forces (SBS) campaign has frozen the Azov Sea and the Kerch Strait, Brovdi said.

134 in the Azov, 166 in the Black Sea

SBS drones struck 134 vessels in the Azov Sea and 166 in the Black Sea since Operation MoLoChKa began on 6 July, the SBS wrote—all, Brovdi specified, stripped of the ability to move under their own power. He called it the "300th fleet," playing on the Ukrainian army's code for a wounded man, and "a suitcase without a handle and a torment for the worm budget."

The Azov Sea "stands and will stand, together with the Kerch Strait," Brovdi said. The northern and northeastern Black Sea operates on what he called a "maybe we'll slip through" gamble.

The 300-ship count is the latest in a rapid progression. The SBS reported 201 vessels disabled by 29 July—just three weeks into the operation—when Brovdi said Crimea's supply route was "blocked indefinitely." By 11 September, the tally had reached 285, with 215 struck in July, 54 in August, and 16 in the first 11 days of September. The pace slowed as traffic in the strike zone thinned out.

The SBS figures are the unit's own and cannot be independently verified.

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Ukraine hits 201 Russian shadow fleet ships in three weeks. Commander says Crimea’s supply route is now blocked indefinitely

Commercial shipping retreating from Russian ports

In late August, MSC Mediterranean Shipping Co., the world's largest container carrier, suspended new bookings for transport through the Russian port of Novorossiysk. Russia itself closed the Don-Azov shipping channel and the Kerch Strait in July after the opening wave of strikes.

By early August, Ukraine had turned Novorossiysk—Russia's main Black Sea export gateway—into a chokepoint, and in mid-August Ukrainian forces struck four Russian warships there in a single night. A 141-meter vessel disappeared near Novorossiysk the same week.

A parallel campaign against Crimea's power grid

The SBS is running a second operation alongside MoLoChKa. Operation Crimean Switch Off, also launched on 6 July, had struck 374 energy nodes across occupied Crimea and other occupied areas in eastern and southern Ukraine by 10 September. The campaign has blacked out Crimea on multiple nights. Brovdi has said the SBS could strike seven times more targets with faster funding.