Ukraine Sees Russian-Iranian Sanctions Networks Converging As US Targets Tankers

WASHINGTON -- The recent US destruction of five Iranian oil tankers in the Strait of Hormuz has exposed more than the widening confrontation between Washington and Tehran.

It has highlighted an increasingly intertwined sanctions-evasion system linking Iran and Russia -- a network of ships, managers, intermediaries, and trading routes that Ukrainian officials and US sanctions experts say the West can no longer treat as two separate problems.

Three of the five tankers -- Kaviz, Charminar, and Riesco -- had direct links to Russia’s shadow oil fleet, according to Vladyslav Vlasiuk, Ukrainian President Volodymyr Zelenskyy’s sanctions commissioner.

All three transported Russian oil and called at Russian ports, Vlasiuk told RFE/RL on September 10. Riesco, he said, carried both Russian and Iranian oil and participated in ship-to-ship transfers involving other sanctioned vessels.

“Russia and Iran have a long history of cooperation, and their sanctions-evasion networks increasingly overlap,” Vlasiuk said.

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Philip Luck, director of the Economics Program at the Center for Strategic and International Studies and a former deputy chief economist at the US State Department, described the system more bluntly: “There’s not a Russian shadow fleet and Iranian shadow fleet. There’s one shadow fleet that is facilitating Iranian oil sales and Russian oil sales.”

Tankers Tied To Moscow

Kaviz operated between the Russian ports of Ust-Luga and Novorossiysk and had a history of switching off its automatic identification system, which allows authorities and other vessels to track ships. Vlasiuk linked it to Fractal Marine DMCC, a network involved in moving Russian oil after Western sanctions were imposed.

Charminar repeatedly called at Russian ports, including Ust-Luga, Primorsk, Vysotsk, and St. Petersburg. Vlasiuk said it was connected to a shipping network controlled by Iranian oil businessman Mohammad Hossein Shamkhani.

After Britain sanctioned Fractal Marine, vessels connected to the network were transferred to other managers while their Russian oil operations continued, Vlasiuk said.

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Riesco illustrates the two-way nature of the trade. It carried both Russian and Iranian oil and participated in ship-to-ship transfers involving other sanctioned vessels.

All three tankers are sanctioned by Ukraine and the United States, according to Vlasiuk. Kaviz is also sanctioned by the European Union, Britain, Canada, and Switzerland.

Vlasiuk did not estimate how much revenue the vessels generated for Russia. Their importance, he said, lies in helping Russian oil reach global markets despite Western restrictions.

“These vessels were part of the infrastructure that enabled Russian oil to keep reaching the global market despite sanctions, allowing Russia to preserve a major source of revenue,” he said.

For Ukraine, that infrastructure is itself a target. “The same vessels, masters, managers, intermediaries and shipping routes are used to transport both Russian and Iranian oil,” Vlasiuk said.

One Fleet, Two Oil Trades

Luck said the implications extend beyond the three ships because Russia and Iran sell oil to many of the same markets. That creates a challenge for sanctions policymakers: measures aimed at one country’s oil trade may affect the other because the logistics are shared.

“So anything, if you want to put more pressure on Iran, you’re gonna be putting more pressure on Russia,” Luck said. “And if you put more pressure on Russia, you’re putting more pressure on Iran. It’s the exact same problem.”

The issue has become more urgent as Washington combines economic pressure on Tehran with direct military action. The US says the Iranian tankers were part of a shadow network helping finance Iran’s Islamic Revolutionary Guard Corps and its proxies. The strikes followed Iranian attacks on US naval forces, while Secretary of State Marco Rubio has warned that Washington will respond to further attacks.

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The confrontation has also increased pressure on energy markets. Washington and Tehran are seeking influence over the Strait of Hormuz, through which roughly one-fifth of global oil supplies passed before the war.

For Kyiv, the tanker strikes show why maritime networks have become an increasingly important sanctions target. “As long as this infrastructure remains operational, opportunities to evade sanctions will remain,” Vlasiuk said.

Ukraine Sees A Wider Russia-Iran Link

The episode comes as Washington considers expanding its ability to target Russia’s energy revenues and the networks helping Moscow evade sanctions.

The Lindsey O. Graham Sanctioning Russia and Iran Act of 2026 passed the Senate on August 7 by 86-11. It targets Russia’s shadow fleet, imposes additional sanctions on Russian officials and financial institutions, and authorizes the president to impose duties of up to 100 percent on goods from major purchasers of Russian oil and gas and countries involved in sanctions evasion. It also extends the Iran Sanctions Act for five years.

The bill’s future in the House remains uncertain, but Ukraine says it could provide leverage against Russia, whose energy revenues remain central to financing the war.

At a September 10 briefing hosted by the Bipartisan Congressional Ukraine Caucus, Ukraine’s Charge d’Affaires in Washington, Denys Sienik, urged lawmakers to view the measure as a source of leverage rather than a finished instrument.

“All the decisions, major decisions, indeed require compromise,” Sienik said. He warned that Russia continues earning substantial oil and gas revenues while producing weapons and recruiting soldiers.

“What message will it send to Ukrainians, and what message will it send to Russia if this does not pass?” he asked.

Former State Department sanctions coordinator Daniel Fried offered a similar assessment. “If the US authority would increase diplomacy to end Russia’s war against Ukraine, it should increase the leverage it’s using against Russia,” he said. “Now is the time to use it.”

Fried cited the Obama administration’s Iran policy, when Congress pressured the administration to threaten countries buying Iranian oil while allowing waivers for nations that significantly reduced purchases over six-month periods. China and India protested but ultimately reduced their imports.

He said the current bill could likewise give Washington room to negotiate with major buyers rather than automatically impose maximum penalties. Fried acknowledged questions about how the bill’s thresholds would be calculated and how authorities would determine the destination of Russian oil.

“But with this bill, if it passes, there is something to work with,” he said. “There is leverage. If it doesn’t pass, there is nothing, zero.”

Fried said sanctions need not eliminate every barrel of Russian or Iranian oil from global markets. Their goal is to reduce the revenue available to sustain war. Forcing Russia to sell at lower prices, he said, can also reduce money flowing to the Kremlin.

That approach places the shadow fleet at the center of the sanctions debate. The objective is not simply to stop individual ships, but to make the networks moving sanctioned oil more expensive, unreliable, and difficult to replace.

Ukraine’s argument is that those networks are already shared by Russia and Iran. The three tankers identified by Kyiv offer a case study: vessels moving Russian oil, Iranian oil, or both; managers shifting between sanctioned networks; and ship-to-ship transfers helping cargoes reach international markets.

As Washington escalates pressure on Tehran and considers additional measures against Moscow, that convergence could become increasingly important.