WASHINGTON (CN) – The Treasury Department imposed a fresh round of sanctions Tuesday against Russian actors it believes are trying to evade U.S. pushback against Kremlin-ordered cyberattacks.

The newly sanctioned individuals and companies were targeted for acting on behalf of sanctioned firm Divetechnoservices, a St. Petersburg company that supplies underwater equipment and diving systems to the Russian government, including its intelligence agency the Federal Security Service.

The Treasury Department had pointed to a cyberattack in Ukraine last year that targeted the country’s financial system with the ransomeware NotPetya, along with cyber intrusions into the U.S. energy grid when it sanctioned Divetechnoservices back in June.

Treasury said Tuesday that the new sanctions will freeze the assets of Russian individuals Marina Igorevna Tsareva and Anton Aleksandrovich Nagibin, along with Russia-based firm Vela-Marine Ltd. and Slovakia-based firm Lacno S.R.O., which tried to facilitate a $20,000 payment for Divetechnoservices.

According to the Treasury Department, Divetechnoservices wanted to use Lacno S.R.O. to buy equipment.

Treasury Secretary Steven Mnuchin lauded the new sanctions, which he said are disrupting Russian efforts at evasion.

“Today’s action against these deceptive actors is critical to ensure that the public is aware of the tactics undertaken by designated parties and that these actors remain blocked from the U.S. financial system,” Mnuchin said in a statement.

During a hearing Tuesday morning before the Senate Banking, Housing and Urban Affairs Committee, Treasury Department official Sigal Mandelker said the U.S. sanctions regime against Russia has “blocked hundreds of millions of dollars in Russian assets in the United States and caused extensive damage to the economic interests of affected individuals and entities.”

The testimony from Mandelker, whose title is acting treasury deputy secretary, says some of Russian President Vladimir Putin’s closest associates are among the 217 Russia-connected on whom the Trump administration has slapped sanctions since January 2017.

Mandelker also credited the economic pressure of the sanctions with persuading Exxon to halt its joint exploration ventures with Russian petroleum company Rosneft, while Russian aluminum tycoon Oleg Deripaska’s net worth has dropped about 50 percent.

The Treasury Department sanctioned two Russian shipping companies as well Tuesday, saying it suspects them of having violated United Nations sanctions by transferring petroleum products to North Korea.