The US imposed sanctions on Russian and Slovakian firms for actions to help another Russian company avoid sanctions over cyber-related activities. Picture: AP Photo/Pablo Martinez Monsivais

Washington - The United States on Tuesday imposed sanctions on two Russians, one Russian company and one Slovakian firm for what Washington said were their actions to help another Russian company avoid sanctions over the country's malicious cyber-related activities.

The US Treasury said in a statement that the sanctioned companies - Saint Petersburg-based Vela-Marine Ltd and Slovakia-based Lacno S.R.O. - and the two individuals helped Divetechnoservices evade previously imposed sanctions.

In June, the United States sanctioned Divetechnoservices, also based in Saint Petersburg, for procuring underwater equipment and diving systems for Russian government agencies, including Russia's FSB intelligence agency.

The Obama administration sanctioned the FSB in December 2016, citing the Russian government's aggressive harassment of US officials and cyber operations aimed at the 2016 US presidential election.

In its statement, the US Treasury said the two individuals sanctioned on Tuesday - Marina Igorevna Tsareva and Anton Aleksandrovich Nagibin - had both helped Divetechnoservices attempt to circumvent U.S. sanctions.

The head of Vela-Marine told Reuters he did not understand why his firm was being designated. Speaking by telephone, Andrei Kuklin, head of the company, said: "Unfortunately I cannot comment. I don't understand what the problem is."

Reuters was unable to immediately determine contact information for Lacno, which does not have its own website and which does not list any contact number on the Slovak finance ministry registry of firms website.

Nagibin did not answer a call seeking comment. Reuters was not immediately able to identify contact information for Tsareva.