The activities of Russia’s shadowy “Internet Research Agency,” which pumped out divisive social media content in an attempt to drive Americans apart, continue to come to light. According to disclosures made to Congress, the troll farm’s posts reached 126 million Facebook users in the U.S. over the last couple of years.
The operation also put over 131,000 messages on Twitter and 1,100 videos on YouTube, according to the disclosures, reported Monday in The New York Times, ahead of congressional hearings this week on the matter of Russian interference in last year’s election.
Facebook previously told Congress about 3,000 ads that it said reached 10 million Americans, in an apparent campaign to divide people on issues ranging from race to gun rights. Now, it’s talking about around 80,000 pieces of content that initially reached 29 million people, some of whom then showed them to tens of millions more.
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Facebook’s Instagram photo-sharing service also played host to around 120,000 of “Russia-linked content,” the Times reported the company as saying. Facebook fb apparently deleted over 170 Instagram accounts as a result.
According to prepared remarks by Facebook general counsel Colin Stretch, the firm is “determined to prevent it from happening again.”
As for Twitter twtr , the microblogging service identified and suspended over 2,700 Internet Research Agency-linked accounts that posted around 131,000 tweets between September and November 2016. It also identified another 36,000 Russia-linked bots that pumped out 1.4 million tweets over the same period—tweets that were viewed around 288 million times.
Google googl , meanwhile, found and suspended 18 YouTube channels that were probably also the work of Russian agents. However, the company said there was no evidence that the channels’ 1,100 videos were targeting Americans in particular—they also had relatively low numbers of views. The Internet Research Agency also bought $4,700 in Google search and display ads, the firm said, adding that none of these targeted web-surfers by their political leanings.
The volume of the Russian operatives’ output on social media is of course noteworthy, pointing as it does to the effort they made to exploit wedge issues in the U.S. at a critical time. However, it remains unclear as to what extent this effort worked. Facebook in particular tends to show people what it thinks they want to see, so much of this content may have ended up reinforcing people’s existing beliefs rather than convincing them to change their minds.
However, the concerted push may have had some effect in swaying the election to Donald Trump, and this week’s revelations do appear to help fill in part of a larger picture. Also on Monday, the Federal Bureau of Investigation revealed its first charges in its investigation of possible collusion between the Trump campaign and the Kremlin.