The US justice department has indicted 12 Russian intelligence officers for hacking Democratic officials in the 2016 election.
Deputy Attorney General Rod Rosenstein said the dozen accused used spear phishing emails and malicious software in the cyber-attacks.
Special Counsel Robert Mueller’s inquiry is looking into alleged Russia meddling in the 2016 election.
The investigation has already indicted 20 people and three companies.
What’s in the indictment?
The indictment says the named Russian intelligence officers began their cyber-attacks in March 2016 to hack the email accounts of volunteers and employees of Hillary Clinton’s presidential campaign.
Mr Rosenstein said the defendants corresponded with several Americans during the alleged conspiracy, but added there is no allegation that any US citizen committed a crime.
The alleged conspirators hacked into the computer network of the Democratic Congressional Campaign Committee (DCCC) and Democratic National Committee (DNC).
He said: “The defendants covertly monitored the computers, implanted hundreds of files containing malicious computer code, and stole emails and other documents.”
The indictment states that the conspirators searched a campaign committee computer specifically for terms including “Hillary”, “Cruz”, “Trump” and “Benghazi Investigations”.
Mr Rosenstein said the conspirators created fictitious online personas, including “DCLeaks” and “Guccifer 2.0”.
They allegedly used these identities to release thousands of stolen emails and other documents beginning in June 2016.
He said: “We know that the goal of the conspirators was to have an impact on the election.
“What impact they may have had, what their motivation may have been independently of what’s required to prove this offence, is a matter of speculation. That’s not our responsibility.”
The deputy attorney general said he had briefed President Donald Trump about the indictments earlier in the week.
Mr Trump, who is in the UK, had repeatedly dismissed the investigation a “witch hunt”.
The indictment comes just three days before the president is scheduled to meet with Russian President Vladimir Putin at a summit in Helsinki.
Who are the defendants?
The Russians indicted are not in US custody nor is it likely that they will ever serve jail time.
The deputy attorney general said all 12 of the defendants worked were military officers in the Russian intelligence service, the GRU.
Mr Rosenstein said they worked for two units: one was involved in actively stealing information while the other was responsible for disseminating this stolen information.
What’s the big picture?
The Mueller inquiry is looking into US intelligence findings that Russians conspired to tilt the election in Mr Trump’s favour, and whether any of his campaign aides colluded with this alleged plot.
The investigation has already indicted 20 people – mostly Russian nationals – as well as three companies and four former Trump advisers.
None of the charges allege Trump advisers colluded with Russia to interfere with the presidential campaign.
Former National Security Adviser Michael Flynn and George Papadopoulos, a former foreign policy adviser, have pleaded guilty to making false statements about their contacts with Russians.
Former Trump campaign chairman Paul Manafort and his deputy Rick Gates were charged with money laundering relating to their political consultancy work in Ukraine.