Tumblr has deleted 84 accounts which it claims were used by the Kremlin to spread disinformation during the 2016 US presidential election.
The site claimed the accounts were linked to the so-called Internet Research Agency (IRA), a private company based in St Petersburg, which spread disinformation during the election.
In February, the IRA and 13 Russian nationals were charged with illegally interfering in US politics.
Tumblr said the accounts on its platform had been shut down, the posts they had made were deleted, and US law enforcement had been involved.
It said the continuing investigation into Russian interference in the US election had prevented it from making these actions public until now.
In a statement, the company said: “We’re committed to transparency and want you to know everything that we know.
“We’ve decided to leave up any reblog chains that might be on your Tumblrs – you can choose to leave them or delete them.
“We’re letting you decide because the reblog chains contain posts created by real Tumblr users, often challenging or debunking the false and incendiary claims in the IRA-linked original post.”
It added that it would use email to notify “anyone who liked, reblogged, replied to, or followed an IRA-linked account with the list of usernames they engaged with”.