Facebook CEO Mark Zuckerberg. Getty

Facebook on Wednesday said it had found evidence that fake accounts "likely operated out of Russia" purchased thousands of ads during the US presidential election designed to amplify divisive political messages.

Facebook said the ads were part of elaborate "information operations" in which "organized actors," including governments, used social media to deceive the public and distort political sentiment.

Facebook conducted an examination of ads purchased over the past two years in response to mounting concern over "Russian interference in the electoral process" and Facebook's role in spreading misinformation leading up to the election according to Facebook's chief security officer, Alex Stamos.

The company discovered roughly $100,000 in ad buys between June 2015 and May 2017 "associated with roughly 3,000 ads" and connected to nearly 500 affiliated fake accounts.

"Our analysis suggests these accounts and Pages were affiliated with one another and likely operated out of Russia," Stamos wrote in a post published on Facebook's company blog.

The "vast majority" of ads related to the fake Russian accounts didn't target a political candidate and instead focused on "amplifying divisive social and political messages across the ideological spectrum," according to Stamos. He said the company had shared its findings with US authorities investigating Russia's interference in the election.

The revelation follows months of reports linking Russia to efforts designed to sway November's US presidential election between Donald Trump and Hillary Clinton. But Facebook's announcement marks the first official confirmation by the company that its 2-billion-member platform was likely exploited during the election.

A sharp turnaround

The revelation follows months of reports linking Russia to efforts designed to sway November's US presidential election between Donald Trump and Hillary Clinton. Carlos Barria/Reuters

Wednesday's announcement by Facebook represents a sharp turnaround from the company's previous remarks on its role in the spread of fake news during the election.

For example, Facebook said in July that it had found "no evidence that Russian actors bought ads on Facebook in connection with the election."

The social network was widely criticized after the election for its role in the proliferation of so-called fake news, which many believe helped Donald Trump win the election. CEO Mark Zuckerberg initially called that notion "pretty crazy," but Facebook has since made significant strides to eradicate fake-news stories from its platform.

In a research paper published earlier this year, Facebook detailed its attempts to thwart organized "information operations" that are increasingly used to sway political leanings through the spread of fake news and propaganda on its platform.

"Through the adept use of social media, information operators may attempt to distort public discourse, recruit supporters and financiers, or affect political or military outcomes. These activities can sometimes be accomplished without significant cost or risk to their organizers," Facebook wrote in the April report.

Facebook said Wednesday that its analysis of ads purchased before and after the US presidential election were consistent with the information operation tactics it had previously outlined. About one-quarter of the ads were geographically targeted, and most touched on divisive topics, from LGBT rights to immigration and gun rights, the company said.