The spies allegedly targeted computers belonging to the Democratic Party and its 2016 presidential candidate, Hillary Clinton. The charges were issued as part of a wider probe into US President Donald Trump.
A US grand jury has indicted 12 Russian intelligence officers for stealing information on 500,000 voters and hacking Democratic Party computers during the 2016 US presidential election, the US Justice Department said on Friday.
Deputy Attorney General Rod Rosenstein announced the charges drawn up by Special Counsel Robert Mueller, the lead investigator in an ongoing probe into possible collusion between the US President Donald Trump's 2016 campaign and the Russian government.
The spies allegedly gained access to the voters' information after hacking a state election board. They are also accused of stealing emails from Democratic Party computers, including devices belonging to Democratic presidential candidate Hillary Clinton's campaign team, and then releasing them online months before the November 7 election.
A Kremlin official has denied the accusations, telling reporters in Moscow that Russia did not interfere and had no intention of interfering in the 2016 US presidential elections.
"When the Americans have facts, we will take a look - that's what our president has said multiple times," said Yuri Ushakov, a foreign policy adviser to Russian President Vladimir Putin.
Latest charges against Russians
Rosenstein said he informed Trump of the charges earlier in the week.
"Free and fair elections are hard-fought and contentious and there will always be adversaries who work to exacerbate domestic differences and try to confuse, divide and conquer us," he said.
The indictment is the first time Mueller has explicitly charged the Russian government with election meddling. The US special counsel has already filed separate charges against 13 Russians and three Russian companies for their alleged involvement in a concerted campaign to influence the outcome of the 2016 election.
Democratic Party leaders in the US Congress called on Trump, who is set to meet Putin at a summit in the Finnish capital of Helsinki on Monday, to press his Russian counterpart on the meddling .
"President Trump should cancel his meeting with Vladimir Putin until Russia takes demonstrable and transparent steps to prove that they won't interfere in future elections," Senate Democratic leader Chuck Schumer said.
House Democratic leader Nancy Pelosi urged Trump to secure a pledge from Putin not to interfere again in US elections. "Failure to stand up to Putin would constitute a profound betrayal of the constitution and our democracy," she said
Trump rails against probe, again
On Friday, Trump complained the Mueller investigation was undermining the US relationship with Russia.
"We do have a — a political problem where — you know in the United States we have this stupidity going on. Pure stupidity," he said, referring to the Mueller investigation. "But it makes it very hard to do something with Russia."
US National Intelligence Director Dan Coats said on Friday that "warning lights" about cyber threats to US national security are "blinking red."
Coats added that US officials have detected cyber threats targeting energy, water and other infrastructure, aviation networks and manufacturing facilities and come from Russia, Iran, China and North Korea as well as criminal networks and independent hackers.
"Today the digital infrastructure that serves this country is literally under attack," Coats told a think-tank audience.
"Every day foreign actors ... are penetrating our digital infrastructure and conducting a range of cyber intrusions and attacks against targets in the United States."
"In regards to state actions, Russia has been the most aggressive foreign actor, no question. And they continue their efforts to undermine our democracy," he added.