Deputy Attorney General Rod Rosenstein announced that Mueller's team has indicted 12 Russian intelligence officials for the hack of Democratic National Committee, the Democratic Congressional Campaign Committee, and Hillary Clinton's campaign chairman John Podesta.
Deputy Attorney General Rod Rosenstein said there was sufficient evidence to present the charges to a grand jury.
The indictments were filed by Special Prosecutor Robert Mueller, who is investing possible collusion between the presidential campaign of President Donald Trump and the Russian spies USA intelligence agencies say interfered with the 2016 election.
In addition to the DNC hack, the defendants are charged with a separate conspiracy to "to infiltrate computers of organizations responsible for administering elections, including state boards of election, secretaries of state, and companies that supply software and other technology used to administer elections".
An embargo on the indictment was lifted prior to Rosenstein's announcement when a reporter in the main Department of Justice briefing room broke the information by reading a press release over a hot mic.
Mueller's probe has come under sustained attack from Trump and his supporters in Congress, who call it a witch hunt and a politically-motivated attempt to hurt the president.
The Russia investigation has now led to charges against 32 people, including previous charges against 14 Russian nationals for their work on spreading Russian-based propaganda.
Rosenstein, who said he had briefed President Donald Trump on the indictment, said there was no allegation that the hacking altered any vote count or that any Americans were knowingly in communication with any of the Russian officers.
Mr Rosenstein said there were no allegations that United States citizens were involved in the alleged crimes. "When we confront foreign interference in American elections, it is important for us to avoid thinking politically as Republicans or Democrats and instead to think patriotically as Americans".