WASHINGTON, United States (AFP) — Facebook says it has suspended the account of Cambridge Analytica, the data analysis firm hired by Donald Trump’s 2016 presidential campaign, after reports it harvested the profile information of millions of US voters without their permission.

According to the New York Times and Britain’s Observer, the company stole information from 50 million Facebook users’ profiles in the tech giant’s biggest-ever data breach, to help them design software to predict and influence voters’ choices at the ballot box.

Also suspended were the accounts of its parent organisation, Strategic Communication Laboratories, as well as those of University of Cambridge psychologist Aleksandr Kogan and Christopher Wylie, who runs a firm called Eunoia Technologies.

Cambridge Analytica was bankrolled to the tune of US$15 billion by US hedge fund billionaire Robert Mercer, a major Republican donor. The Observer said it was headed at the time by Steve Bannon, a top Trump adviser until he was fired last summer.

“In 2015, we learned that … Kogan lied to us and violated our Platform Policies by passing data from an app that was using Facebook Login to SCL/Cambridge Analytica, a firm that does political, government and military work around the globe,” Facebook said in a posting late Friday by its vice president and deputy general counsel Paul Grewal.

Kogan also improperly shared the data with Wylie, it said.

Kogan’s app, thisisyourdigitallife, offered a personality prediction test, describing itself on Facebook as “a research app used by psychologists.”

Some 270,000 people downloaded the app, allowing Kogan to access information such as the city listed on their profile, or content they had liked.

“However, the app also collected the information of the test-takers’ Facebook friends, leading to the accumulation of a data pool tens of millions-strong,” the Observer reported.

Wylie, who later became a whistleblower, told the newspaper: “We exploited Facebook to harvest millions of people’s profiles. And built models to exploit what we knew about them and target their inner demons. That was the basis that the entire company was built on.”

Kogan legitimately obtained the information but “violated platform policies” by passing information to SCL/Cambridge Analytica and Wylie, Facebook said.

Facebook, which did not say how the data was used or misused, said it removed the app in 2015 when it learned of the violation, and was told by Kogan and everyone who received the data that it had since been destroyed.

“Several days ago, we received reports that, contrary to the certifications we were given, not all data was deleted,” Grewal wrote.

“We are moving aggressively to determine the accuracy of these claims. If true, this is another unacceptable violation of trust and the commitments they made.

“We are suspending SCL/Cambridge Analytica, Wylie and Kogan from Facebook, pending further information.”

The New York Times reported that copies of the data harvested for Cambridge Analytica were still online and that its team had viewed some of the raw data.

Cambridge Analytica, the US unit of British behavioural marketing firm SCL, rose to prominence as the firm that the pro-Brexit group Leave.EU hired for data-gathering and audience-targeting.