The United States has warned Russian oligarchs and corporations that it is monitoring their financial transactions for any signs of evading Ukrainian war-related sanctions and tracking those who provide them with “material support.”

A senior U.S. Treasury official said Washington has taken notice wealthy russians and companies The transfer of wealth and money has been concealed in the month since Western governments began imposing sanctions on Russia over its war in Ukraine. The United States is also tracking those who have not yet been sanctioned.

The official told the FT that wealthy Russians, already proficient at hiding assets to evade taxes, were taking advantage of “loophole” capital controls imposed by Moscow as part of their efforts to prevent the financial system from collapsing.

“We are seeing the transfer of wealth to new employees and the creation of shell companies. We are watching these initiatives,” the official said, adding that Russian banks and companies are Adopt technology That oligarch It has been used for years to cover their tracks.

The official praised Western cooperation in sanctions enforcement, which means violators risk not only losing access to the U.S. financial system, but also transactions denominated in euros and pounds.

G7 countries and Australia are forming a working group to track the assets of sanctioned individuals and those who could be targeted by future measures.

While some European capitals have expressed doubts about secondary U.S. sanctions — restricting individuals and companies in other countries from doing business with U.S. entities — Washington’s partners have pledged to rely on other countries to cooperate. G7 leaders Commitment last week In order to “get other governments to impose similar restrictions,” they have implemented it.

The U.S. wants to take further action to reduce Russia’s military equipment by limiting Moscow’s ability to buy foreign-made parts critical to prolonging the war, the official said.

The official added that Washington will target “critical nodes in the supply chain” to weaken Russia’s armed forces and its defense industry, which still rely on Western technology.

“We will keep going, as long as the invasion continues, we will keep going,” the official said.

The official pointed out, rare public appearance Russian Defense Minister Sergei Shoigu showed in a video released Saturday discussing a military procurement meeting that Moscow had suffered heavy losses on the battlefield, making it difficult to replace captured or destroyed weapons.

The official said Western cooperation on export controls would leave other countries with no choice but to comply or risk losing the right to use critical U.S. technology in their manufacturing.

“Countries may not like it, but they do it because the alternatives are worse,” the official warned.

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U.S. Commerce Department moves export controls this month to deny Russia entry semiconductortelecommunications, information security equipment, lasers and sensors, if they contain U.S. technology — even if they are manufactured outside the U.S.

In turn, if a country exports these products to Russia without a U.S. license, it could be banned from using U.S. components.

“No country wants to lose that,” the official said, noting that China, for example, does not yet have the capacity to produce cutting-edge chips.

Washington believes the sanctions will cause lasting damage to the Russian economy. Many of the retaliatory measures announced since Russian President Vladimir Putin launched an invasion of Ukraine on February 24 have only come into effect in the past few days.

The official said the U.S. was determined to prevent Russia from “using its power” in the future, suggesting sanctions could be long-term, adding that a ceasefire could peace agreement Even before any sanctions issues are lifted.

“Ukraine has to reach an agreement with Russia before we can consider sanctions,” he said.