Russian President Vladimir Putin on Friday denied his country’s involvement in the cyber attack on the Democratic Party's National Committee in the United States, which led to the release of more than 20,000 emails and documents by WikiLeaks, Bloomberg reported. Investigative agencies in the US had blamed hackers backed by Russia for the computer network breach. “I want to tell you again, I don’t know anything about it, and on a state level, Russia has never done this,” Putin said.

In an interview with the media group, the Russian president called the data leak a service to the public. He said that by bringing up “minor issues with the search for who did it”, there was “no need to distract the public’s attention from the essence of the problem” that was highlighted by the release of the documents.

However, a cyber security analyst at the Center for Strategic and International Studies in Washington said Putin’s denials were not credible, claiming that Russia’s “track record” of state-sponsored hacking was at least a decade old. Furthermore, a cyber-security firm that conducted an internal probe of the DNC hacking had blamed two groups connected with Russian intelligence services and its Defence Ministry for the breach.

The documents had revealed that top officials at the DNC secretly planned to undermine Bernie Sanders’ presidential campaign. Some of the messages show that the committee discussed the prospect of using Sanders’ religious beliefs to sabotage his campaign, The Intercept reported. The emails also revealed the identities of donors and other details like phone numbers, passport and social security numbers.

The leak caused a controversy before the party’s national convention, forcing the committee’s chairperson, Debbie Wasserman Schultz, to step down from her position. WikiLeaks head Julian Assange had said that the organisation plans to release further data on the Democratic Party's presidential nominee, Hillary Clinton’s campaign.