President Obama at his desk in the Oval Office on February 11, 2011.
The U.S. government has sanctioned Russia's main two intelligence agencies, four military intelligence officers and is kicking out 35 Russian diplomats over what it says was aggressive harassment of U.S. officials and cyber operations around the 2016 presidential election.
The move follows up on a pledge made by President Obama to retaliate against Russia for hacks of the Democratic National Committee and other political targets.
It includes newly declassified details of how the hack took place and lists signatures for malware used by the hackers.
It also includes a list of IP addresses associated with the hackers, who have also targeted think tanks, universities and corporations around the world.
"Network defenders can use this information to identify and block Russian malware, forcing the Russian intelligence services to re-engineer their malware," the government said in a statement.