A Russian propaganda arm oversaw a criminal and espionage conspiracy to tamper in the 2016 US presidential campaign to support Donald Trump and disparage Hillary Clinton, said an indictment released on Friday that revealed more details than previously known about Moscow's purported effort to interfere.
The office of US Special Counsel Robert Mueller charged 13 Russians and three Russian companies, including St Petersburg-based Internet Research Agency known for its trolling on social media. The official who oversees Mueller's work said the investigation was not finished.
The court document said those accused "had a strategic goal to sow discord in the US political system, including the 2016 US presidential election."
The indictment said Russians adopted false online personas to push divisive messages; travelled to the United States to collect intelligence, visiting 10 states; and staged political rallies while posing as Americans. In one case, it said, the Russians paid an unidentified person to build a cage aboard a flatbed truck and another to wear a costume "portraying Clinton in a prison uniform."
The surprise 37-page indictment could alter the divisive US domestic debate over Russia's meddling, undercutting some Republicans who, along with Trump, have attacked Mueller's investigation.
"These Russians engaged in a sinister and systematic attack on our political system. It was a conspiracy to subvert the process, and take aim at democracy itself," said Paul Ryan, Republican Speaker of the House of Representatives.
The indictment is silent on the question of whether the Trump campaign colluded with the Kremlin, which Mueller is investigating.
In a tweet on Friday, Trump gave his most direct acknowledgement that Russia had meddled in the election, which he has frequently disputed.
"Russia started their anti-US campaign in 2014, long before I announced that I would run for President. The results of the election were not impacted. The Trump campaign did nothing wrong - no collusion!" Trump wrote.
Russian Foreign Ministry spokeswoman Maria Zakharova denounced the allegations as "absurd" and ridiculed the notion that so few Russian nationals could undermine US democracy.
"13 against the billions' budgets of the secret services?" she asked in a Facebook post.
The accused Russians are unlikely to be arrested or to appear in a US court on the charges, which include conspiracy to defraud the United States, wire fraud, bank fraud and identity theft. There is no extradition treaty between the United States and Russia.