Facebook has said as many as 126 million American users may have seen content uploaded by Russia-based operatives over the last two years.
The social networking site said about 80,000 posts were produced before and after the 2016 presidential election.
Most of the posts focused on divisive social and political messages, reports the BBC.
Facebook released the figures ahead of a Senate hearing where it - together with Twitter and Google - will detail Russia's impact on the popular sites.
Russia has repeatedly denied allegations that it attempted to influence the last US presidential election, in which Donald Trump beat Hillary Clinton.
The latest figures released by Facebook have been seen by Reuters news agency and the Washington Post newspaper.
The 80,000 posts were published between June 2015 and August 2017.
Facebook said they were posted by a Russian company linked to the Kremlin.
"These actions run counter to Facebook's mission of building community and everything we stand for," wrote Facebook's general counsel Colin Stretch, Reuters reports.
"And we are determined to do everything we can to address this new threat."
On Monday, Google also revealed that Russian trolls uploaded more than 1,000 videos on YouTube on 18 different channels, according to the Washington Post.
Twitter found and suspended all 2,752 accounts that it had tracked to Russia-based Internet Research Agency, a source familiar with the company's written testimony was quoted as saying by Reuters.
Meanwhile, a former Trump campaign foreign policy adviser has pleaded guilty to making a false statement to the FBI after he lied about his interactions with foreign officials close to the Russian government -- the campaign's clearest connection so far to Russia's efforts to meddle in the 2016 election.
In addition, former Trump campaign chairman Paul Manafort and former Trump campaign official Rick Gates surrendered Monday to Justice Department special counsel Robert Mueller.
The charges against top officials from Trump's campaign signals a dramatic new phase of Mueller's wide-ranging investigation into possible collusion between the Russian government and members of Trump's team as well as potential obstruction of justice and financial crimes.
BDST: 1310 HRS, OCT 31, 2017
AP
