By Jack Stubbs
LONDON (Reuters) - The leak and distribution of classified British-U.S. trade documents online is tied to a previous Russian disinformation campaign, Reddit said on Friday, fuelling fears that Moscow is seeking to interfere in Britain's upcoming election.
The opposition Labour Party said on Nov. 27 the classified documents showed the ruling Conservatives were plotting to offer the state-run National Health Service for sale in trade talks with Washington.
The NHS is much loved by Britons and has become an important issue in the Dec. 12 election, in which Labour trails the Conservatives despite cutting its lead in some opinion polls.
Reuters reported on Monday that the way the documents were initially shared online resembled a disinformation campaign uncovered earlier this year.
That operation, known as Secondary Infektion, stemmed from a network of social media accounts which Facebook (NASDAQ:FB) said "originated in Russia."
"We were recently made aware of a post on Reddit that included leaked documents from the UK," Reddit said in a statement. "We investigated this account and the accounts connected to it, and today we believe this was part of a campaign that has been reported as originating from Russia."
The company said it has also identified a further network of accounts which had attempted to promote the original post with the leaked documents.
"All of these accounts have the same shared pattern as the original Secondary Infektion group detected, causing us to believe that this was indeed tied to the original group."
A Labour spokesman declined to comment on how the party obtained the leaked documents or ties to the Russian campaign.
"These documents reveal the plot against our NHS. And of course neither the UK nor the US government have denied their authenticity," he said. "Our releasing them to journalists was clearly in the public interest."
The British government said in a statement it was "already looking into the matter" with support from the National Cyber Security Centre, part of the GCHQ signals intelligence agency.
"Online platforms should take responsibility for content posted on them, and we welcome the action Reddit have taken today," it said.
Britain goes to the polls next week in an election called by Prime Minister Boris Johnson to try to break the Brexit deadlock in parliament more than three years since the country voted to leave the European Union.
The country's security agencies have warned that Russia and other countries may attempt to disrupt the vote with cyberattacks or divisive political messages on social media.
The Kremlin has repeatedly denied allegations of election meddling. Officials in Moscow were not immediately available for comment after hours on Friday.