The hearing was the second in Congress this week in which social media and internet firms including Google and Twitter have been called to explain how fake news and other disinformation was allowed to spread during the election campaign.
The Senate Intelligence Committee hearing proved far more explosive than a similar hearing Tuesday by the Senate Judiciary Committee, with senators accusing the social media companies of permitting a flood of Russian-sponsored disinformation aimed at USA voters.
"I went home last night with profound disappointment".
"I wish your three CEOs were here", Sen. It plans to hire thousands of more employees to monitor ads, for example, which will be expensive.
Just before the 2016 USA presidential election, a Russian-backed group with 217,000 Facebook followers posted an illustration that depicted Hillary Clinton as a devil fighting Jesus.
Democrats and Republicans both said the tech companies need to do more to police against foreign government abuse on their platforms.
"I hear all your words, but I have more than a little bit of frustration that many of us on this committee have been raising this issue since the beginning of this year, and our claims were frankly blown off by the leadership of your companies, and dismissed", Sen.
"We're investing so much in security that it will impact our profitability", CEO Mark Zuckerberg said in a written statement provided along with the earnings numbers. "Your earliest presentations showed a lack of resources, a lack of genuine effort and a lack of commitment". "The idea that you had no idea of any of this happening, strains my credibility".
USA intelligence agencies have concluded that the "influence campaign" was aimed at undermining US democracy and helping Donald Trump beat Hillary Clinton in the election.
"These operations, they're not limited to 2016 and not limited to the presidential race, and they continue to this day". He noted that some who attended the events said they noticed that no one from the organizing group was there.
Numerous social media posts came from the Internet Research Agency, which has been linked to Russian intelligence efforts to disrupt the United States election.
During the hearings, Facebook downplayed the potential reach of ads bought by Russia's Internet Research Agency.
Warner explained how users can get lured to a page like "Army of Jesus", by encouraging users to like the page if they "want Jesus to win".
Wednesday's results came right after Facebook wrapped up its third congressional hearing on Capitol Hill where its top lawyer, Colin Stretch, answered questions about the Kremlin-linked Russian influence campaign.
"What neither side could have known is that Russian Federation trolls were encouraging both sides to battle in the streets and create division between real Americans", Burr said.
Lawyers for all three companies stressed that they did take the problem seriously and outlined some of the steps they have been taking to improve their checks on bad actors.