Facebook officials revealed that Russian "troll farms" -- likely operated by the Kremlin -- had purchased $100,000 in ads
, just a few months after saying they had seen no evidence of Russian purchases. The dollar amount is small but those ads, rather than pushing a simple message, likely plugged users into a propaganda network by asking them to "Like" certain groups, one Hill source familiar with briefings said Thursday.
"This is just the tip of the iceberg," said Sen. Mark Warner, the top Democrat on the Senate intelligence committee
, who has been pressing Facebook for months to cooperate with Russia investigators.
Warner noted that the ads directed users to like certain Facebook groups, which could then be used to either influence votes or, more likely he said, depress voter turnout in certain areas.
"The Russians used resource and media platforms to try to interfere with our elections, and I think the fact that they may only have mentioned a particular candidate in a few of the ads is reflective of the fact that there's ways to do voter suppression without mentioning a candidate's name," Warner said. "I think that the American people deserve to know both the content and the source of the information that is being used to try to affect their votes."
Facebook stunned investigators Wednesday when it announced Russian "troll farms" had purchased ads on the platform through hundreds of fake accounts -- a statement that appeared to contradict a comment to CNN months earlier that they had not discovered any evidence of Russians buying ads.
Facebook officials showed Hill investigators Wednesday copies of the ads -- but they refused to give them copies or any other documents, leaving some investigators feeling burned Wednesday.
"We are continuing to cooperate with appropriate authorities and have shared the results of our internal inquiries to this point. And of course, we will continue to review what Russians could have done to manipulate the platform," a Facebook official said.
A source familiar with Facebook's internal review said that the company first began tracking suspected fake accounts associated with the Russians in the spring, but did not discover the ad buys until later in the summer. Facebook officials are still conducting their own internal review, the source said.
Rep. Adam Schiff, the top Democrat on the House intelligence committee's Russia investigation, said Wednesday he wants Facebook executives to appear before the committee in public. Rep. Michael Conaway
, the Texas Republican leading the House investigation, said the public needs to learn more about Russian use of botnets and other propaganda tools.
Sources familiar with the House investigation said that Facebook's House briefing only opened the door to more questions. But the question now is how they will get those questions answered, the sources said.
One House source said that Russia's apparent use of Facebook ads to sign users up for propaganda streams was "insidious."
Conaway said he plans to talk with Schiff about holding a hearing with Facebook and others on Russia's use of social media. Warner also said that he expects to hear from officials for Twitter.
The spotlight on Facebook comes as both Hill probes and the federal probe directed by Special Counsel Robert Mueller are ramping up their investigations. The sprawling examinations have touched on Trump's family, with son-in-law Jared Kushner speaking with Hill investigators and Donald Trump Jr. meeting with the Senate judiciary committee Thursday.
But interest in the digital component of Russia's efforts has waxed and waned -- with Republicans broadly dismissing theories pushed by Democrats that the Trump campaign could have coordinated the targeting of fake news with Russian operatives on Facebook and other platforms.
The House intelligence committee sent an invitation to the Trump campaign's digital director Brad Parscale
over the summer, and Parscale said he would happily testify. Parscale and other members of the Trump campaign's digital team have flatly said they had no interactions with any Russians and were unaware of any interactions.
The House and Senate intelligence committees have actively subpoenaed top-tier witnesses, using their heaviest tool in the ongoing Russia investigations. And subpoenas to former national security adviser Michael Flynn and former Trump Organization lawyer Michael Cohen prefaced the return of key documents to investigators.
But as of Thursday, House and Senate investigators were still mulling how to extract more information from Facebook. One source said that lawmakers were apprehensive about immediately subpoenaing Facebook because they don't want to start a full-on war with the company.