Facebook has suspended tens of thousands of apps as part of an investigation it launched in the wake of the Cambridge Analytica data harvesting scandal.
The suspended apps were associated with about 400 developers, it said.
Facebook said not all the apps posed a threat to users.
The company came under huge pressure in 2018 after it was revealed that Cambridge Analytica had accessed many users' data without permission.
The political consultancy firm is alleged to have used this data - harvested by a personality quiz - to target political advertising.
Facebook was fined $5.0bn in July by the US Federal Trade Commission, in what was believed to have been the biggest ever fine imposed on any company for violating consumers' privacy.
Why is Facebook suspending apps?
The Cambridge Analytica scandal, which involved the data of tens of millions of people, was hugely damaging for Facebook and the company has since faced lawsuits and international criticism.
It is now seeking to improve its privacy safeguards and its image.
As part of that, in March last year Facebook launched an investigation into apps on its platform, involving hundreds of lawyers, data scientists and engineers.
"Our review helps us to better understand patterns of abuse in order to root out bad actors among developers," the company's vice-president for product partnerships, Ime Archibong, said in a statement on Friday.
What do we know about the apps?
Facebook has released little specific information on the tens of thousands of apps or hundreds of developers in question.
The statement said that the suspension of the apps was not necessarily an indication that they posed a threat to people.
"Many were not live but were still in their testing phase when we suspended them," Mr Archibong said.
In some cases developers were subjected to in-depth questioning after being flagged.
Some apps were banned completely for reasons including inappropriately sharing data obtained from Facebook or making data publicly available without protecting people's identity.
One banned app called myPersonality was found to be sharing information with researchers and companies with only limited protections in place, and then refused to take part in an audit, according to Facebook.
The app review is ongoing.