Leaked documents used by Jeremy Corbyn to claim the Tories are planning to sell off the NHS have been linked to a Russian interference campaign on Reddit, the social media platform has said.
Reddit said it had banned 61 accounts following an investigation of suspect activity.
The campaign shared the same pattern of activity as a Russian operation dubbed "Secondary Infektion" uncovered by Facebook earlier this year.
Mr Corbyn used the leaked documents as evidence the Government was at an advanced stage of negotiations with the US to open up the health service to American pharmaceutical companies.
Reddit said it believed the documents were leaked as "part of a campaign that has been reported as originating from Russia".
Culture Secretary Nicky Morgan said it was "extremely serious" that the leaked documents could be linked to a Russian interference campaign.
Speaking to BBC Radio 4's Today programme, Ms Morgan said: "I understand from what was being put on that website, those who seem to know about these things say that it seems to have all the hallmarks of some form of interference.
"And if that is the case, that obviously is extremely serious. And actually as Culture Secretary, obviously one of the things that we are looking for and monitoring is any interference in our elections."
Shadow transport secretary Andy McDonald renewed calls for the Government to allow a report detailing Russian interference in UK elections to be published.
"This has the hallmarks of Russian interference."
Culture secretary, @NickyMorgan01 responds to discussion site Reddit linking leaked documents cited by Jeremy Corbyn to a Russian disinformation campaign.#Ridge#GE2019
Follow live updates here: https://t.co/Iy0QVy2gbnpic.twitter.com/bZZGNBCH9O
— Sophy Ridge on Sunday (@RidgeOnSunday) December 7, 2019
He said: "If we want to get to the bottom of the extent to which the Russian state interferes in elections, can we please publish the Intelligence and Security Committee report?
"Let's get that out there. That should have been published ages ago."
In a statement, Reddit said its investigation had found a "pattern of co-ordination" between the now-banned accounts on its site and a Russian campaign uncovered by Facebook earlier this year.
Information from the investigation into the "Secondary Infektion" campaign on Facebook was used to identify suspect accounts on Reddit.
Reddit said: "This group provides us with important attribution for the recent posting of the leaked UK documents, as well as insights into how adversaries are adapting their tactics.
"As a result of this investigation, we are banning... 61 accounts under our policies against vote manipulation and misuse of the platform. "
Speaking at a news conference last month, Mr Corbyn said the 451 pages left Boris Johnson's claim the the NHS wouldn't be part of trade talks "in absolute tatters".
There is currently no suggestions the documents were false or doctored in any way.
Reddit said the leaked files had first been posted in October and then reposted by a second account.
Pockets of accounts had worked together to "upvote" the posts using vote manipulation to make them more visible to users of the platform, it added.
These accounts had posted in different regional subreddits and in several different languages.
"As we have done with previous influence operations, we will also preserve these accounts for a time, so that researchers and the public can scrutinize them to see for themselves how these accounts operated," Reddit said.
Labour again refused to discuss the source for the documents.
"These documents reveal the plot against our NHS. And of course neither the UK nor the US government have denied their authenticity. Our releasing them to journalists was clearly in the public interest," a Labour spokesman said.