US officials have sanctioned more than a dozen Russian individuals and companies for alleged meddling in the 2016 Presidential election.
They say that state-sponsored agents spread fake news online and even organised faux rallies on US soil ahead of the vote.
A second group of people and two Russian intelligence agencies were also sanctions for major cyber attacks targeting key infrastructure including the nuclear, energy and aviation sectors.
The US Treasury said it had detected large-scale interference by "government cyber actors" since at least 2016, when Donald Trump faced Democrat Hillary Clinton in the Presidential contest.
It said the Russian company The Internet Research Agency LLC (IRA) was at the centre of efforts to mislead voters by creating a "vast number of fake online personas" posing as US citizens that "reached millions of people online".
"The IRA also organized and coordinated political rallies during the run-up to the 2016 election, all while hiding its Russian identity."
Two other companies and 13 individuals were sanctions for assisting the IRA and colluding in its meddling, the Treasury said.
Among those named as a sanctions target is Yevgeny Prigozhin, who has become known as the chef to Russian President Vladimir Putin.
A further six individuals and two Russian state inteliigence agencies - the FSB and the Main Intelligence Directorate - were also sanctioned for staging major cyber attacks.
These include the huge "NotPetya" cyber attack which hit Europe and America in 2017, described today by US officials as the "most destructive and costly" in history.
The Trump administration has also accused Russia of a deliberate operation to penetrate the US energy grid which is still continuing.
National security officials say the FBI, the Homeland Security Department and intelligence agencies have determined that Russian intelligence and others are behind attacks on the American energy sector.
The officials say the Russians obtained access to the energy system and "conducted network reconnaissance" of industrial control systems that run US factories and the electricity grid.
Treasury Secretary Steven Mnuchin said: “The administration is confronting and countering malign Russian cyber activity, including their attempted interference in US elections, destructive cyber-attacks, and intrusions targeting critical infrastructure."