Voting systems in 21 states were targeted by Russian hackers during the 2016 US presidential election, American officials told the US Congress during a hearing on Wednesday (21 June). Officials are yet to reveal the names of the states that were reportedly targeted by Kremlin-linked hackers.

"As of right now, we have evidence that election-related systems in 21 states were targeted," Jeanette Manfra, acting deputy undersecretary of cyber security Department of Homeland Security (DHS) said, adding that there was no evidence to indicate that the cyberattack altered actual ballots, the BBC reported.

Samuel Liles, DHS acting director of the Office of Intelligence and Analysis Cyber Division confirmed that although some voting systems were breached, the attacks did not affect voter tallies. Liles said the hackers were scanning voter systems for vulnerabilities, which he likened to walking down the street, past homes, scoping out weaknesses to break into the place, the Washington Post reported.

"I think the primary goal (of the 2016 effort) in my mind was to sow discord, and to try to de-legitimise our free and fair election process," FBI Counterintelligence Division Assistant Director Bill Priestap said, CNN reported. "I also think another of their goals, which the entire United States intelligence community stands behind, was to denigrate Secretary (Hillary) Clinton and to try to help then, current President (Donald) Trump."

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Priestap added that Russia has been conducting campaigns regarding US elections "for years" but that the Kremlin has now stepped up its game. "Yes, absolutely they've conducted influence operations in the past, what made this different in many regards is of course the degree and what you can do through electronic systems today," Priestap said. "The scale and aggressiveness of the effort in my opinion made this one different, and again, it's because of the electronic infrastructure ... that allowed Russia to do things that in the past they were unable to do."

The White House is yet to comment on the matter.

Moscow has previously dismissed allegations of hacking and interference in US elections. However, the US IC (intelligence community), as well as various independent cybersecurity experts have attributed the cyberattacks that occurred during the 2016 US election, including those that targeted the DNC, to hacker groups affiliated with the Kremlin.