A US Senate hearing to reform an internet law and hold tech companies accountable for how they moderate content quickly turned into a political scuffle.
Lawmakers are split on ways to hold Big Tech accountable under Section 230 of the Communications Decency Act - which protects companies from liability over content posted by users but also lets the firms shape political discourse.
The chief executives of Twitter, Facebook and Google called the law crucial to free expression on the internet. They said Section 230 gives them the tools to strike a balance between preserving free speech and moderating content, even as they appeared open to suggestions the law needs moderate changes.
All three chief executives also agreed the companies should be held liable if the platforms act as a publisher but denied being the referees over political speech - a claim that angered some Republicans.
Senator Ted Cruz went after Twitter's Jack Dorsey when the chief executive said Twitter has no influence over elections.
"Who the hell elected you and put you in charge of what the media are allowed to report and what the American people are allowed to hear," Cruz said. Ahead of the hearing, the senator released a picture on Twitter titled "Free Speech showdown Cruz vs Dorsey" that showed him and Twitter's Dorsey pitted against each other.
Democratic Senator Brian Schatz said he did not have any questions, calling the hearing "nonsense".
"This is bullying and it is for electoral purposes," he said.
Other Democrats including Tammy Baldwin, Ed Markey and Amy Klobuchar also said the hearing was held to help President Donald Trump's re-election effort.
President Donald Trump, who alleges the companies' stifle conservative voices, and Republican lawmakers sent a flurry of tweets as the hearing continued. "Repeal Section 230!" Trump tweeted. Separately, Senator Josh Hawley took a jab at Twitter's Dorsey. "This level of idiocy confirms the widespread impression that Jack's primary food source is weed."
Twitter's global vice president of communications Brandon Borrman said: "There's nothing in the [Hawley] tweet that deserves a response."
Twitter's Dorsey warned the committee that eroding the foundation of Section 230 could significantly hurt how people communicate online. Pichai said Google operates without political bias and that doing otherwise would be against its business interests.
The committee was unable to establish contact with Facebook's Zuckerberg and declared a short recess. He appeared shortly after and said: "I was having a hard time connecting myself."
Zuckerberg said he supports changing the law but also warned that tech platforms are likely to censor more to avoid legal risks if Section 230 is repealed.
No more 'free pass'
Republican Senator Roger Wicker, who chairs the committee, said it was important to shield companies from liability without giving them the ability to censor content they dislike.
"The time has come for that free pass to end," he said.
Wicker also criticised Twitter's decision to block the New York Post stories about Biden's son and Facebook's move to limit their reach.
He and other senators such as Cory Gardner went after Twitter for not taking down tweets from world leaders that allegedly spread misinformation but going aggressively after Republican President Donald Trump's tweets.
Zuckerberg told lawmakers a warning from the FBI on hack-and-leak operations before the US presidential election played a role in its decision to limit the reach of those stories from the New York Post.
He said it had seen attempts by Russia, Iran and China to run disinformation campaigns.
"One of the threats that the FBI has alerted our companies ... to was the possibility of a hack and leak operation in the days or weeks leading up to this election," he said.
"So you had both public testimony from from the FBI ... in private meetings alerts that were given to at least our company, I assume the others as well, that suggested that we be on high alert and sensitivity that if a trove of documents appeared that that we should view that with suspicion that it might be part of a foreign manipulation attempt."
US lawmakers are not the only ones pushing for reform. The European Union's executive Commission is drafting a new Digital Services Act that, in addition to tackling market abuses by dominant platforms, would also address liability for harmful or illegal content.
Competition Commissioner Margrethe Vestager is due to unveil her proposals on 2 December.