WASHINGTON (NewsNation Now) — Senators grilled the CEOs of Facebook and Twitter on their companies’ actions around the closely contested election between President Donald Trump and Democrat Joe Biden.

Twitter CEO Jack Dorsey and Facebook CEO Mark Zuckerberg testified via video at a Senate Judiciary Committee hearing Tuesday.

Republican senators questioned Dorsey and Zuckerberg for what they considered to be censorship of Trump and his allies. Meanwhile, Democrats turned their focus to claims that the president and his supporters spread misinformation.

Both platforms have placed misinformation labels on some of the president’s content. Most of the flagged posts were Trump’s assertions linking voting by mail to fraud.

Dorsey said Tuesday that Twitter flagged about 300,000 tweets as part of efforts to combat disinformation during the election period between Oct. 27 and Nov. 11. Of the labeled tweets, 456 also were covered by a warning message and were limited in how they could be shared. About 74% of the people who viewed those tweets saw them after a label or warning message was applied.

In his written testimony for the hearing, Dorsey said, “We applied labels to add context and limit the risk of harmful election misinformation spreading without important context, because the public told us they wanted us to take these steps.”

The hearing comes a day after Twitter flagged Trump’s tweet proclaiming “I won the Election!” with this note: “Multiple sources called this election differently.”

Zuckerberg said Tuesday that Facebook joined with election officials to remove false claims about polling conditions and displayed warnings on more than 150 million pieces of content after review by independent fact-checkers. Facebook also prohibited misrepresentations about how or when to vote as well as attempts to use threats on the coronavirus to scare people into not voting, he said.

Zuckerberg acknowledged that “election interference remains an ongoing threat.”

Republican Sen. Lindsey Graham, the Senate Judiciary Committee’s chairman, accused the platforms of anti-conservative bias, and pushed for stripping away some of the protections that have shielded tech companies from legal responsibility for what people post.

“I think there’s Republican and Democratic concern about the power that’s being used by social media outlets to tell us what we can see and what we can’t, what’s true and what’s not,” Graham said.

Democratic senators called for the companies to limit the spread of false and misleading content ahead of elections in Georgia, where two Republican incumbent senators, David Perdue and Kelly Loeffler, are facing run-offs against well-funded Democratic opponents.

Sen. Richard Blumenthal, a Connecticut Democrat, told the executives that actions the companies took to slow the spread of disinformation in the presidential election were constructive. But Blumenthal said he was concerned they could let their guard down for the Georgia elections and fail to act against dangerous information.

“You have an immense civic and moral responsibility,” he said.

Both companies committed to doing more. 

Zuckerberg and Dorsey promised lawmakers last month that they would aggressively guard their platforms from being manipulated by foreign governments or used to incite violence around the election results.

Two days after the election, Facebook moved to ban a large group called “Stop the Steal” that Trump supporters were using to organize protests against the vote count. The 350,000-member group echoed Trump’s allegations of a rigged election rendering the results invalid.

As the post-Election Day vote counting went on, copycat “Stop the Steal” groups were easily found on Facebook. As of Monday, Facebook appeared to have made them harder to find, though it was still possible to locate them, including some groups with thousands of members.

The GOP majority on the Judiciary panel threatened Zuckerberg and Dorsey with subpoenas last month if they didn’t agree to voluntarily testify for Tuesday’s hearing. Republicans on the Senate Commerce Committee lambasted the two CEOs and Sundar Pichai, Google’s chief executive, at a hearing last month for what they said was a pattern of silencing conservative viewpoints while giving free rein to political actors from countries like China and Iran.

Despite fears over security in the run-up to Nov. 3 and social media companies bracing for the worst, the election turned out to be the most secure in U.S. history, federal and state officials from both parties say — repudiating Trump’s unsubstantiated claims of fraud.

Facebook insists it has learned its lesson from the 2016 election and is no longer a conduit for misinformation, voter suppression and election disruption. This fall Facebook said it removed a small network of accounts and pages linked to Russia’s Internet Research Agency, the “troll factory” that has used social media accounts to sow political discord in the U.S. since the 2016 election. Twitter suspended five related accounts.

But critical outsiders, as well as some of Facebook’s own employees, say the company’s efforts to tighten its safeguards remain insufficient, despite it having spent billions.

“Facebook only acts if they feel there’s a threat to their reputation or their bottom line,” says Imran Ahmed, CEO of the Center for Countering Digital Hate. The organization had pressed Facebook to take down the “Stop the Steal” group.