FACEBOOK DATA WAS HARVESTED

Facebook's chief executive has revealed that his data was among that harvested in a privacy scandal.

Mark Zuckerberg made the disclosure during his second day of being questioned in Washington.

In a related development, the political consultancy at the heart of the affair has announced its acting chief executive is stepping down.

He also revealed that his firm was exploring whether to take action against the University of Cambridge.

The institution is where the researcher Aleksandr Kogan, who had collected and sold personal data to Cambridge Analytica, was based.

"What we found now is that there's a whole programme associated with Cambridge University where... there were a number of other researchers building similar apps," Mr Zuckerberg said.

"So, we do need to understand whether there was something bad going on at Cambridge University overall that will require a stronger reaction from us."

The university has reacted by saying it would be "surprised" if Mr Zuckerberg was only now aware of the work.

"Our researchers have been publishing such research since 2013 in major peer-reviewed scientific journals, and these studies have been reported widely in international media," it added.

"These have included one study in 2015 led by Dr Aleksandr Spectre (Kogan) and co-authored by two Facebook employees.

"We have found no evidence that University researchers are improperly gathering personal data."

Mr Zuckerberg had earlier apologised for having failed to check in 2015 that Cambridge Analytica had deleted information gathered about millions of Facebook users.

Instead Facebook let the political consultancy self-certify that it had destroyed the records, which it said had been acquired in violation of the social network's rules.

"We have a responsibility to make sure what happened with [app developer] Kogan and Cambridge Analytica doesn't happen again," Mr Zuckerberg said.

The 33-year-old added that Facebook's audit of other apps would take many months to complete. But he said that the firm had seen no evidence as yet that Russia or China had attempted to scrape people's information.