While he still faces Congressional testimony next week, Facebook CEO Mark Zuckerberg faced fresh scrutiny during a media conference call today as the company continues to cope with the effects of the Cambridge Analytica data scandal.

Zuckerberg said he was “quite confident” in the company’s analysis showing that no more than 87 million users were affected by the data breach, 71 million of them Americans. That estimate is substantially higher than the previous estimate of 50 million-plus that stemmed from a whistleblower revealing Cambridge Analytica’s tactics when the research firm was working on behalf of Donald Trump’s 2016 campaign.

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Thibault Camus/AP/REX/Shutterstock
REX/Shutterstock

The conference call brought an ominous revelation with implications far beyond Cambridge Analytica, when Zuckerberg conceded that most of the company’s 2 billion global users have had their data “scraped” without authorization. In acknowledging the realities of the Facebook environment, the founder described his creation as “an idealistic and optimistic company“ that “didn’t focus enough on preventing abuse.” He called it a “huge mistake” that he hadn’t been more focused on preventing abuse via the platform.

Zuckerberg said he regretted dismissing the notion that fake news could do harm as “crazy” shortly after Trump’s historic win. “What is clear at this point is that it was too flippant,” he said.

Asked if Facebook’s board had asked him to step down as chairman, Zuckerberg replied, “Not that I am aware of.”

In a response after the Facebook call, Cambridge Analytica asserted that it had licensed data from no more than 30 million people via research company GSR. The firm also asserted that it did not use any GSR data in its work in the 2016 presidential election, and that insisted that it had immediately expunged all GSR data from its systems after Facebook alerted it to the breach.

The saga has trimmed some value from Facebook. Shares have plunged 16% over the past three weeks, though they have perked up 3% in after-hours trading. They slipped another fraction during the official trading day, closing at $155.10.

Facebook also announced today the details of the most extensive revamp of its privacy settings in several years. The changes tighten controls on a range of activities on Facebook — making groups or events people participate in less visible, for example. Beginning on Monday, the social network will post a link at the top of users’ News Feeds so they can see what apps they are using, along with information they have shared with those apps. Facebook will let users know if their personal data may have been shared with Cambridge Analytica without permission.