Facebook chief Mark Zuckerberg has told a congressional committee his own personal data was included in the massive leak to political consultancy firm Cambridge Analytica.

As Mr Zuckerberg’s testimony over Facebook’s leak of the private data of 87 million users entered its second day, the social media mogul admitted he was among the victims.

Despite repeatedly defending his company’s privacy practices, when asked if his own personal data was included in the data sold to “malicious third parties” he replied: “Yes.”

But Mr Zuckerberg pushed back on congress members’ suggestions that users do not have enough control of their data on Facebook in the wake of the privacy scandal.

“Every time that someone chooses to share something on Facebook … there is a control. Right there. Not buried in the settings somewhere but right there,” the 33-year-old said.

Once again wearing a dark suit instead of his usual grey T-shirt, Mr Zuckerberg took questions for nearly five hours in a US Senate hearing without making any further promises to support new legislation or change how the social network does business, foiling attempts by senators to pin him down.

Facebook has been consumed by turmoil for nearly a month, since it came to light that millions of users’ personal information was wrongly harvested from the website by Cambridge Analytica, a firm that has counted US President Donald Trump’s election campaign among its clients.

As Mr Zuckerberg testified, Cambridge Analytica’s acting CEO Dr Alexander Tayler announced his resignation.

The company released a statement saying Dr Tayler would resume his former position as Chief Data Officer in order to “focus on the various technical investigations and inquiries”.

Mr Zuckerberg has faced broad concerns from members of Congress about how Facebook shares user data.

“How can consumers have control over their data when Facebook does not have control over the data?” asked Representative Frank Pallone of New Jersey.

Lawmakers have sought assurances that Facebook can effectively police itself, and few came away from Tuesday’s hearing expressing confidence in the social network.

“I don’t want to vote to have to regulate Facebook, but by God, I will,” Republican Senator John Kennedy told Zuckerberg on Tuesday. “A lot of that depends on you.”

Mr Zuckerberg deflected requests to support specific legislation. Pressed repeatedly by Democratic Senator Ed Markey to endorse a proposed law that would require companies to get people’s permission before sharing personal information, Zuckerberg agreed to further talks.

“In principle, I think that makes sense, and the details matter, and I look forward to having our team work with you on fleshing that out,” he said.

Mr Zuckerberg also told the hearing that his company has a 200-strong counterterrorism team reviewing flagged posts and informations.

“I think we have capacity in 30 languages that we are working on and in addition to that, we have a number of AI (artificial intelligence) tools that we are developing … that can proactively go flag the content,” he said.