Democratic presidential candidates Elizabeth Warren and Joe Biden are sounding off on Facebook CEO Mark Zuckerberg following Zuckerberg's speech on freedom of expression at Georgetown University on Thursday.

During the 35-minute address, Zuckerberg described Facebook's approach to protecting free speech on the social media platform, which includes allowing paid political advertisements with misinformation.

Biden's campaign accused Zuckerberg of "feigned concern" for free speech and said Facebook is attempting to use the US Constitution as a shield to protect the company's revenue.

Warren said Facebook is accepting millions of dollars for ads with misinformation, which could have an impact on the 2020 presidential election.

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Facebook CEO Mark Zuckerberg's comments on freedom of expression and Facebook's approach to protecting free speech have sparked an intense response from two of the front-running Democratic presidential candidates: former Vice President Joe Biden and Sen. Elizabeth Warren.

Speaking to a live audience at Georgetown University on Thursday, Facebook CEO Mark Zuckerberg defended Facebook's role in providing a voice to more than 2 billion people of around the world. While he admitted that some types of misinformation can do harm, Zuckerberg said that Facebook and other tech companies shouldn't be the ones to decide what information is true.

"While I worry about an erosion of truth, I don't think most people want to live in a world where you can only post things that tech companies judge to be 100% true," Zuckerberg said.

Read more: Facebook's billionaire CEO Mark Zuckerberg addressed threats to free speech in a rare public address on Thursday

Warren has been one of Facebook's most frequent critics, and has repeatedly called for the tech company to be dismantled. Following Zuckerberg's comments at Georgetown, Warren said the speech showed how little Facebook's CEO had learned in the years since the 2016 election, when Russian agents intentionally used the social media platform to influence American voters with fake accounts and misinformation.

Warren said that Facebook's decision to allow paid advertisements with misleading and false information could ultimately influence the 2020 presidential election as well.

Earlier this month Facebook confirmed that paid political ads are ineligible for third-party fact-checking. Other types of ads that include misinformation are not allowed on the social media platform.

Facebook reports that President Donald Trump's re-election campaign spent more than $1.6 million on Facebook ads from September 25 to October 1, according to Facebook's ads library (comparatively, Elizabeth Warren spent $285,000 and Biden spent $122,000 in the same period).

In an email sent to Business Insider minutes after Zuckerberg's speech concluded, a Biden campaign spokesperson said Zuckerberg had "feigned concern for free expression" in an attempt to protect Facebook's business interests.

"Facebook has chosen to sell Americans' personal data to politicians looking to target them with disproven lies and conspiracy theories, crowding out the voices of working Americans," Bill Russo, the Biden campaign's deputy communications director, said in the statement. "Zuckerberg attempted to use the Constitution as a shield for his company's bottom line, and his choice to cloak Facebook's policy in a feigned concern for free expression demonstrates how unprepared his company is for this unique moment in our history and how little it has learned over the past few years."

Facebook did not immediately respond to Business Insider's request for comment on Warren's and Biden's remarks.

The role of Facebook, Twitter, and other social media platforms in American politics has been a core issue of the Democratic primary campaigns. While Warren and Biden remain critical of Facebook, there's no questioning the platform's ability to reach and influence tens of millions of Americans.