"All of these problems I've outlined, and given the scope and the size and reach [Facebook has], it should be clear: while we have serious concerns about your plans to establish a global digital currency that will challenge the U.S. dollar ... we have also opened up a serious discussion about whether Facebook should be broken up", she said.
"I get that I'm not the ideal messenger for this right now".
"If anyone, including a politician, is saying things that can cause - that is calling for violence, or could risk imminent physical harm or voter or census suppression, when we roll out the census suppression policy, we will take that content down".
In his testimony at the start of the hearing, made public Tuesday, Zuckerberg said that he understood lawmakers' queasiness about the Libra project, acknowledging that it was "difficult" to trust Facebook. But Zuckerberg said he views the USA financial system as "outdated", and China, he constantly reminded Congress, is working on its own public-private digital currency partnership with payment processor Alipay, which boasts 900 million users.
Zuckerberg is testifying before the House Financial Services Committee about Facebook's plan to create a global digital currency, as well as other issues.
Zuckerberg is striving to defend Libra and alleviate concerns that the currency could sidestep regulators. This settled with a group including the American Civil Liberties Union, the National Fair Housing Alliance and others, but Facebook still faces an administrative complaint filed by U.S. Department of Housing and Urban Development.
One source at a partner company told the BBC: "We've seen Facebook start to move away from the Association a little bit, maybe, but it's still a challenge for them, definitely".
Zuckerberg has been summoned to testify at a hearing Wednesday by the House Financial Services Committee on Facebook's plan to create a global digital currency, which has stirred opposition from lawmakers and regulators in the US and Europe.
It was a stronger statement than when Facebook official David Marcus appeared before lawmakers in July, when he said the company will not activate Libra until it has "fully addressed regulatory concerns and received appropriate approvals". Speaking to Yahoo Finance, Marcus insisted that Libra was "absolutely not" in jeopardy, while admitting that the project is "going to get harder before it gets easier". Zuckerberg, momentarily at a loss for words, noted that "it's a risky enterprise".
Wagner and California Democrat Brad Sherman expressed alarm that end-to-end encryption could encourage illicit activities. "And I think if you were to run an ad that had a lie, that would be bad".
Zuckerberg warned lawmakers that others around the globe, especially China, were eager to take a leadership role in legitimizing cryptoocurrency.
As well, 46 attorneys general joined a New York-led antitrust investigation of Facebook, it was announced this week. Facebook is also facing criticism from several Democratic presidential candidates for refusing to ban political ads from candidates containing false information.