A Facebook whistleblower whose claims have rocked the social media giant has launched a fresh attack on Mark Zuckerberg, accusing him of not being willing to protect public safety.
The latest broadside by former employee Frances Haugen comes as she prepares to give evidence to MPs at Westminster.
Her intervention ramps up the pressure on the embattled $1trn (£750bn) company, which has been plunged into a crisis since she released thousands of pages of internal research documents secretly copied before leaving her job in the firm's civic integrity unit.
It comes amid newspaper reports that workers repeatedly warned Facebook was being flooded with misinformation claiming that the 2020 US presidential election result was being rigged.
Workers reportedly believed more should have been done to tackle it.
It has fuelled renewed concerns about Facebook's role in the 6 January Capitol riots, in which a mob seeking to overturn the election result stormed Congress.
Separate leaked documents also reveal Facebook in India wavered in curbing hate speech and anti-Muslim content on its platform and lacked enough local language moderators to stop misinformation, which at times sparked violence.
Criticising Facebook CEO Mark Zuckerberg in a interview with The Observer newspaper, Ms Haugen said: "Right now, Mark is unaccountable.
"He has all the control.
"He has no oversight, and he has not demonstrated that he is willing to govern the company at the level that is necessary for public safety."
She said she had leaked the documents because she realised the company would not change otherwise.
Ms Haugen made her comments ahead of facing questions from a UK parliamentary committee scrutinising the draft Online Safety Bill, which aims to regulate tech firms and social media in a bid to curb cyber abuse and threats.
She has already levelled a series allegations against the social network, saying its platforms "harm children, stoke division and weaken our democracy", and that it refused to act because executives put profits above safety.
Ms Haugen has also accused the tech giant of being aware of the apparent harm Instagram could have on some teenagers and their body image, and said the firm had been dishonest in its public fight against hate content and misinformation by concealing research that showed it amplified such content.
Mr Zuckerberg has rejected the claims made by Ms Haugen, saying her attacks on the company were "misrepresenting" the work it does and that it "cares deeply about issues like safety, well-being and mental health".
He added: "At the heart of these accusations is this idea that we prioritise profit over safety and well-being. That's just not true."
Facebook is reportedly planning to rebrand its business name in an apparent bid to distance its wider business from the string of controversies that have engulfed it in recent years.
Among its latest big ideas is the so-called metaverse, a 3D online world the firm wants to lead the way on building, in which people can meet, play and work virtually, often using virtual reality headsets.