Facebook CEO Mark Zuckerberg speaks during the annual F8 summit in San Jose on May 1. (Josh Edelson/AFP)

Facebook said Monday morning that it had suspended roughly 200 apps amid an ongoing investigation prompted by the Cambridge Analytica scandal into whether services on the site had improperly used or collected users' personal data.

The company said in an update, its first since the social network announced the internal audit in March, that the apps would undergo a “thorough investigation” into whether they had misused user data.

Facebook declined to provide more detail on which apps were suspended, how many people had used them or what red flags had led them to suspect those apps of misuse.

CEO Mark Zuckerberg has said the company will examine tens of thousands of apps that could have accessed or collected large amounts of users' personal information before the site's more restrictive data rules for third-party developers took effect in 2015.

The company said teams of internal and external experts will conduct interviews and lead on-site inspections of certain apps during its ongoing audit. Thousands of apps have been investigated so far, the company said, adding that any app that refuses to cooperate or failed the audit would be banned from the site.

The suspensions support a long-running defense of Aleksandr Kogan, the researcher who provided Facebook data to Cambridge Analytica, that many apps besides his had gathered vast amounts of user information under Facebook's previously lax data-privacy rules.

One of the 200 apps, the personality quiz myPersonality, was suspended in early April and is under investigation, Facebook officials said. Researchers at the University of Cambridge had set up the app to collect personal information about Facebook users and inform academic research. But its data may not have been properly secured, as first reported by New Scientist, which found login credentials for the app's database available online.

"This is clearly a breach of the terms that academics agree to when requesting a collaboration with myPersonality," the University of Cambridge said in a statement Monday. "Once we learned of this, we took immediate steps to stop access to the account and to stop further data sharing."

The researchers added that academics who used the tool had to verify their identities and the nature of their research and agree to terms of service that prohibited them from sharing Facebook data "outside of their research group."

A different quiz app, developed by Kogan and tapped by Cambridge Analytica, a political consultancy hired by President Trump and other Republicans, was able to pull detailed data on 87 million people, including from the app's direct users and their friends, who had not overtly consented to the app's use.

The announcement comes ahead of a Wednesday hearing on Capitol Hill focused on Cambridge Analytica and data privacy. Lawmakers on the Senate Judiciary Committee said they would question Christopher Wylie, a former employee at the firm who brought its business practices to light earlier this year, along with other academics.

In the United States, the Federal Trade Commission is investigating whether Facebook’s entanglement with Cambridge Analytica violates its 2011 settlement with the U.S. government over another series of privacy mishaps. Such violations could carry sky-high fines.

Across the Atlantic, meanwhile, the European Parliament is still requesting Zuckerberg come testify in person. A spokesman for Antonio Tajani, the president of the parliament, did not immediately respond to an email seeking comment.

British lawmakers have issued a similar demand, and Facebook told a panel there investigating the company that it would make a decision about Zuckerberg’s potential appearance by Monday. A spokeswoman for the Digital, Culture, Media and Sport Committee said the panel had heard from Facebook but declined to provide further details.

Facebook said users will be able to go to this page to see if they had used one of the suspected apps once the company reveals which apps are under investigation. Company officials would not provide an estimated timeline for that disclosure.