Facebook quickly approved the ad, showing, according to Warren, that the platform's new rules had turned the social media giant into a "disinformation-for-profit machine."
The ad itself eventually discloses that the Zuckerberg endorsement is false and quickly pivots to a warning about Trump. "If Trump lies in a TV ad, most networks will refuse to air it. But Facebook just cashes Trump's checks," she said.
"Facebook holds incredible power to affect elections and our national debate," she said in another tweet. "They’ve decided to let political figures lie to you—even about Facebook itself—while their executives and their investors get even richer off the ads containing these lies."
She went on to claim that Trump's campaign spent $1 million per week on Facebook ads, allegedly including some that wouldn't air on television because they contained false claims.
"Facebook already helped elect Donald Trump once through negligence. Now, they've changed their policy so they can profit from lies to the American people," she said before linking to a petition calling for Zuckerberg to be held "accountable."
In a statement provided to Fox News, Facebook defended its stance on not censoring political speech. “Facebook believes political speech should be protected. If Senator Warren wants to say things she knows to be untrue, we believe Facebook should not be in the position of censoring that speech," a company spokesperson said.
Facebook also pointed to an FCC guideline requiring neutrality in hosting content.
The guideline reads: "Except as other-wise indicated in § 73.1944, no station licensee is required to permit the use of its facilities by any legally qualified candidate for public office, but if any licensee shall permit any such candidate to use its facilities, it shall afford equal opportunities to all other candidates for that office to use such facilities. Such licensee shall have no power of censorship over the material broadcast by any such candidate."
The company previously rejected former Vice President Joe Biden's request to take down a critical ad from the Trump campaign. According to The New York Times, the company defended its decision in a letter to Biden's campaign. Warren's tweet appeared to refer to that particular ad, which both CNN and NBC refused to air.
“Our approach is grounded in Facebook’s fundamental belief in free expression, respect for the democratic process, and the belief that, in mature democracies with a free press, political speech is already arguably the most scrutinized speech there is," wrote Katie Harbath, the company's head of global elections policy.
Warren's stunt came as Facebook faced criticism from conservatives and progressives alike. Conservatives have long railed against social media platforms for apparently showing greater scrutiny over their content and unnecessarily censoring certain information.
Progressives, like Warren, have warned that Facebook could easily be leveraged to help Republicans win re-election. A long-running argument by Democrats is that Russia used Facebook to help Trump win the 2016 election.
Warren, in particular, has taken aim at the social media giant, vowing to break up the company and combat its allegedly anti-competitive practices.
Steve Guest, a spokesman for the Republican National Committee, blasted the Democrat's ad as a "political stunt" and said it "won't distract from Warren's primary goal: giving government the control of your health care and hiking everyone's taxes to pay for it."