Facebook estimates that Russian-backed "inflammatory" content reached as many as 126 million American users during and after the 2016 presidential election.
Twitter and Google, which own other popular social media tools, also had similar experiences of being encroached upon by Russia-backed groups that tried to influence the elections.
The US has accused Russia of meddling in 2016 presidential election which Donald J Trump won.
Facebook Inc said on Monday that Russia-based operatives published about 80,000 posts on the social network site over a two-year period in an effort to sway US politics and that about 126 million Americans might have seen the posts during that time.
Facebook's latest data on the Russia-linked posts - possibly reaching around half of the US population of voting age - far exceeds the company's previous disclosures. It was included in written testimony provided to US lawmakers, and seen by sections of the media, including Reuters and The Wall Street Journal, ahead of key hearings with social media and technology companies about Russian meddling in elections on Capitol Hill this week.
Twitter Inc separately has found 2,752 accounts linked to Russian operatives, a source familiar with the company's written testimony told Reuters. That estimate is up from a tally of 201 accounts that Twitter reported in September.
Google, owned by Alphabet Inc, said in a statement on Monday it had found $4,700 in Russia-linked ad spending during the 2016 US election cycle, and that it would build a database of election ads.
Top officials of the three companies are scheduled to testify before the Senate Judiciary Committee on Tuesday during which they are likely to inform the lawmakers that the figures of Russian penetration in the American social media is much more than previously seen, said multiple media outlets having access to their testimonies.
Facebook will tell Congress that some 126 million US users, a potentially large portion of the voting public here, may have seen stories, posts or other content from Russian sources, according to The Wall Street Journal and other US media.
"Russian agents intending to sow discord among American citizens disseminated inflammatory posts that reached 126 million users on Facebook, published more than 131,000 messages on Twitter and uploaded over 1,000 videos to Google's YouTube service," according to copies of prepared remarks from the companies that were obtained by The New York Times.
The new information goes far beyond what the companies have revealed in the past and underline the breadth of the Kremlins efforts to lever open divisions in the US using American technology platforms, especially Facebook, the daily said.
In a blog post, Google said that it found two accounts linked to the Internet Research Agency spent a total of $SD 4,700 on its platforms during the 2016 election cycle. This figure covers both search and display advertisements.
Google said it found 18 channels likely associated with this campaign that made videos publicly available, in English and with content that appeared to be political.
There were 1,108 such videos uploaded, representing 43 hours of content and totalling 309,000 US views from June 2015 to November 2016.
These videos generally had very low view counts; only around 3 per cent had more than 5,000 views. These channels have been suspended by Google.
In its investigation, Facebook found that the Russia-backed Internet Research Agency purchased 3,000 advertisements worth $100,000.
It also found that 120 pages were created by the group to disseminate its advertisements and posts. The company had previously said that it found 470 total accounts linked to the Internet Research Agency.
Similarly, Twitter found as many as 2,752 accounts associated with Internet Research Agency.
"The new disclosures come as the tech industry is facing the threat of regulation. Tech companies are expected to face tough questions about their advertisements disclosure policy and their opposition to greater regulation," the Journal said.
"The foreign interference we saw is reprehensible and outrageous and opened a new battleground for our company, our industry and our society," Colin Stretch, General Counsel of Facebook said in his prepared testimony.
The Russian government has denied any attempts to sway the election, in which US President Donald Trump, a Republican, defeated Democrat Hillary Clinton.
Facebook's general counsel, Colin Stretch, said in the written testimony that the 80,000 posts from Russia's Internet Research Agency were a tiny fraction of content on Facebook, equal to one out of 23,000 posts.
However, the posts violated Facebook's terms of service, and any amount of such activity using fake accounts is too much, Stretch wrote.
''These actions run counter to Facebook's mission of building community and everything we stand for. And we are determined to do everything we can to address this new threat,'' he wrote.
The 80,000 posts were published between June 2015 and August 2017. Most of them focused on divisive social and political messages such as race relations, Facebook said.
Twitter's revised estimate of how many Russia-linked accounts were on its service comes a month after an influential Democratic senator, Mark Warner, slammed it for what he called an insufficient investigation.