The US has imposed sanctions on 19 Russians, accusing them of interference in the 2016 US election and alleged cyber-attacks.
They include 13 individuals charged last month by Justice Department Special Counsel Robert Mueller.
Treasury Secretary Steven Mnuchin accused the Russians of “destructive cyber-attacks, and intrusions targeting critical infrastructure”.
He said the sanctions would target “ongoing nefarious attacks” by Russia.The measures are being described in Washington as the strongest action taken by the Trump administration thus far against Moscow.
Russia says it has already begun drawing up counter-measures.
Five entities including the Russian military intelligence agency GRU are targeted in Thursday’s sanctions.
Also blacklisted is the St Petersburg-based Internet Research Agency, which is accused of engineering an online disinformation campaign to sway the 2016 US presidential election.
Yevgeny Prigozhin – an oligarch who allegedly ran the agency and is known as “Putin’s chef” – and 12 of the agency’s staff are also hit by the sanctions.
All 13 were charged in a February indictment by US special counsel Robert Mueller, who is investigating allegations that Russia meddled in the US vote to help Donald Trump win.
Under the US sanctions, the Russian Federal Security Service, or FSB, and six of its employees are subjected to penalties for cyber-attacks.
The US treasury secretary said there would be additional sanctions to hold Russian “officials and oligarchs accountable for their destabilising activities”.
He did not specify when these penalties would be imposed, but stated they would sever the individuals’ access to the US financial system.
“The IRA [Internet Research Agency] created and managed a vast number of fake online personas that posed as legitimate US persons to include grassroots organisations, interest groups, and a state political party on social media,” the Treasury Department statement said on Thursday.
“Through this activity, the IRA posted thousands of ads that reached millions of people online.”
The penalties freeze any assets the individuals and entities may have in the US and prohibits American citizens from conducting business with them.
The Trump administration also accused Russia on Thursday of an ongoing operation to hack and spy on the US power utilities.
US officials say the Russians hacked computer systems to conduct “network reconnaissance” of systems that run the American electricity grid and other industrial infrastructure.