Based in Russia and Cyprus, Zimenkov and his son Jonatan Zimenkov undertake deals on behalf of already-sanctioned key Russian defense entities like Rostec and Rosoboronexport, the US Treasury said.

They maintain a global network of companies in Cyprus, Singapore, Belarus, Bulgaria, Uzbekistan and Israel.

Dealings include supplying Russian weapons systems to an African government and helicopters to a Latin American country, and acquiring electro-optic and infrared devices for a Russian firm after the February 2022 invasion of Ukraine, according to a Treasury statement.

Tuesday's sanctions blacklist 22 individuals and entities in the Zimenkov network.

The action was taken as part of the multilateral Russian Elites, Proxies, and Oligarchs Task Force formed in the wake of Russia's attack on Ukraine to target the country's elites and their agents.

"Russia's desperate attempts to utilize proxies to circumvent US sanctions demonstrate that sanctions have made it much harder and costlier for Russia's military-industrial complex to re-supply Putin's war machine," said Deputy Treasury Secretary Wally Adeyemo in a statement.

US Treasury sanctions generally seek to freeze any assets those targeted have under US jurisdiction and ban any American individual or entity, including financial institutions with US branches, from doing business with them.