Fake Facebook accounts spent about $100,000 on ads aimed at influencing US presidential election
Hundreds of fake Facebook accounts spent about $100,000 (£76,000) on ads aimed at stirring up divisive issues such as gun control and race relations during the US presidential election, the social network has said.
Although the number of ads is relatively small, the disclosure provides a more detailed glimpse into what investigators believe was a targeted effort by Russians to influence US politics during the 2016 campaign, this time through social media.
The 470 accounts appeared to come from a notorious "troll farm", a St Petersburg-based organisation known for promoting pro-Russian government positions through fake accounts, according to sources.
The accounts purchased 3,000 ads between June 2015 and May this year.
While the ads did not specifically reference the election, a candidate or voting, they allowed "divisive messages" to be amplified through the social media platform, the company's chief security officer Alex Stamos said.
Facebook has turned over its findings to federal authorities investigating Russian interference in the presidential election.
Robert Mueller, the special counsel, is overseeing the probe into Russian meddling in the US election and any potential co-ordination with associates of President Donald Trump.
Senator Mark Warner, the ranking Democrat on the Senate Intelligence Committee, said Facebook briefed the panel's staff on Wednesday, but he wants to know more.
"I have a lot more questions for Facebook, and I've got a lot of questions for Twitter," Mr Warner said, noting that "we've got Twitter coming in".
He said he also wants to know more about the content of the ads pushed out by the Russian-based Internet Research Agency and whether they targeted specific voters or locations in the US.
He said in many cases the social media messaging "was more about voter depression and suppression without having to necessarily mention an individual candidate's name".
Adam Schiff, the top Democrat on the House Intelligence Committee, said Facebook's disclosure confirmed what many legislators investigating Russian interference in the election had long suspected.
"One of the things that we're interested obviously in finding out is whether there was any coordination in terms of the use of those paid social media trolls or the Russian use of bots," he said.
The fake accounts were discovered during a company review of ad sales that was spurred by a broader investigation the company initiated into Russian meddling after the election, Mr Stamos said.
In addition to the 470 accounts that appeared to be run from Russia, Mr Stamos said investigators discovered $50,000 in spending on 2,200 ads that "might have originated in Russia", including ads purchased by accounts with IP addresses in the US but with Russian language settings.
The amount of ad spending identified by Facebook is infinitesimal compared with the total amount spent during the election. According to ad tracker Borrell Associates, more than $1.4 billion was spent during the election cycle on digital advertising alone. That figure includes spending on national, state and local elections.