The White House has announced an array of sanctions against Russia for meddling in US elections and for broader hacking efforts, including one incident it called "most destructive and costly cyberattack in history."

The US government unveiled the sanctions Thursday morning, saying they were prompted by Russia's online propaganda campaign during the US elections, massive hacks of Yahoo and attempted cyberattacks against electrical grids in the US.   

The government singled out Russia's role in the NotPetya attack, a piece of malware that was disguised as ransomware but actually designed to destroy data. Last month, the Trump Administration attributed the attack to Russia, saying it caused billions of dollars in damage in Europe, Asia and the Americas.  

"These targeted sanctions are a part of a broader effort to address the ongoing nefarious attacks emanating from Russia," Treasury Secretary Steven Mnuchin said in a statement. The sanctions, he said, will "hold Russian government officials and oligarchs accountable for their destabilizing activities by severing their access to the US financial system."

The sanctions come after an investigation by the Department of Homeland Security and the FBI. 

The sanctions fall on 19 individuals and five Russian entities, including the Internet Research Agency, a trolling farm designed to meddle in the 2016 presidential election through divisive posts on social media. They also target Russia's intelligence agency, known as the Federal Security Service or FSB, and the country's military intelligence organization, the GRU. 

The Russian embassy didn't respond to a request for comment.

Senior national security officials said the FSB was directly involved in hacking millions of Yahoo accounts, while the GRU was behind the interference in the 2016 presidential election and the NotPetya cyberattack. 

The sanctions fall under the Countering America's Adversaries Through Sanctions Act, which authorizes pushback against "aggression by the governments of Iran, the Russian Federation and North Korea."

Investigators found evidence of Russian attempts to hack into the US electric grid through spear-phishing tactics, senior national security officials said. The attacks have been going on since March 2016, targeting multiple US government offices, as well as energy, water, nuclear and critical manufacturing companies.

The DHS and the FBI provided details in a technical alert released Thursday, calling the actions a "multistage intrusion" through which Russian hackers were able to gain remote access into energy sector networks.

Originally published March 15 at 7:32 a.m. PT.
Updated at 7:58 a.m. PT: Added more details on Russian hacking efforts.

Security:  Stay up-to-date on the latest in breaches, hacks, fixes and all those cybersecurity issues that keep you up at night. 

The Smartest Stuff: Innovators are thinking up new ways to make you, and the things around you, smarter.