Facebook said it would begin notifying users Monday if their data has been swept up in the Cambridge Analytica scandal, although it appears to be taking its time.

The 87 million users who might have had their data shared with Cambridge Analytica were supposed to get a detailed message on their news feeds starting on Monday. Facebook says more than 70 million of the affected users are in the U.S., though there are over a million each in the Philippines, Indonesia and the U.K.

As of 8:30 p.m. Eastern time, however, there were no signs that any users have yet received that notification or a more general one Facebook said it would direct to everyone on its service. Associated Press reporters around the world have been surveying users, none of whom have reported seeing anything from Facebook. There appear to be no social media reports of notifications, and Facebook had no immediate comment on the matter.

Reeling from its worst privacy crisis in history — allegations that this Trump-affiliated data mining firm may have used ill-gotten user data to try to influence elections — Facebook is in full damage-control mode. CEO Mark Zuckerberg acknowledged that he made a "huge mistake" in failing to take a broad enough view of what Facebook's responsibility is in the world. He's set to testify before Congress on Tuesday and Wednesday.

In prepared remarks released by a House committee, Zuckerberg said the company has notified all users affected in the scandal. Since the remarks are for Wednesday morning, this means everyone who was affected should see a message by then.

Cambridge Analytica whistleblower Christopher Wylie previously estimated that more than 50 million people were compromised by a personality quiz that collected data from users and their friends. In an interview aired Sunday on NBC's "Meet the Press," Wylie said the true number could be even larger than 87 million.

That Facebook app, called "This is Your Digital Life," was a personality quiz created in 2014 by an academic researcher named Aleksander Kogan, who paid about 270,000 people to take it. The app vacuumed up not just the data of the people who took it, but also — thanks to Facebook's loose restrictions — data from their friends, too, including details that they hadn't intended to share publicly.

Facebook later limited the data apps can access, but it was too late in this case.

Zuckerberg said Facebook came up with the 87 million figure by calculating the maximum number of friends that users could have had while Kogan's app was collecting data. The company doesn't have logs going back that far, he said, so it can't know exactly how many people may have been affected.

Cambridge Analytica said in a statement last Wednesday that it had data for only 30 million Facebook users.

Facebook has also suspended two more apps in recent days because they might have misused people's data, adding to a growing list of firms being investigated by the social media company.

Facebook said CubeYou, a firm associated with the University of Cambridge Psychometrics Centre, will be suspended after CNBC notified Facebook that CubeYou was collecting information about users through quizzes.

According to CNBC, CubeYou labeled its quizzes "for non-profit academic research" then shared user information with marketers. CNBC says CubeYou denies misusing data.

On Saturday, Facebook said it suspended AggregateIQ, a Canadian political consulting firm, amid media reports it had ties to Cambridge Analytica.