Facebook has admitted hiring a PR firm to attack billionaire Jewish philanthropist George Soros after he criticised the social media giant.
The company's outgoing head of communications and policy, Elliot Schrage, said earlier this year he had asked public relations firm Definers to target Mr Soros after he criticised the company.
Facebook is replacing Mr Schrage with former British deputy prime minister Nick Clegg.
At the Davos business summit in January, Mr Soros called Facebook and Google a "menace to society" and accused them of exploiting the social environment in the same way that mining and oil companies exploited the physical environment.
Mr Soros, 88, has been vilified by the political right for his support of politically liberal causes, and has been especially criticised by anti-Semites.
Facebook's outgoing head of communications said he took full responsibility for the decision to target the famous investor, and said neither chief executive Mark Zuckerberg nor chief operating officer Sheryl Sandberg were aware of it.
Mr Schrage, who did not specifically apologise for targeting George Soros, wrote that Facebook had asked the PR firm to identify the figures behind the "Freedom from Facebook" campaign.
When they learned that the Open Society Foundation had funded several of the coalition members they "prepared documents and distributed these to the press to show that this was not simply a spontaneous grassroots movement", Mr Schrage wrote.
Through the Open Society Foundation, Mr Soros has contributed to numerous liberal political causes, including making a £400,000 donation to anti-Brexit campaign Best for Britain.
His philanthropy has prompted anti-Semitic conspiracy theories accusing Mr Soros of being behind many politically progressive initiatives, and criticism of the billionaire has become increasingly mainstream.
Mr Soros was among a number of people who has been criticised by President Trump and was targeted by an explosive device found in a mailbox near his home.
The very rude elevator screamers are paid professionals only looking to make Senators look bad. Dont fall for it! Also, look at all of the professionally made identical signs. Paid for by Soros and others. These are not signs made in the basement from love! #Troublemakers
— Donald J. Trump (@realDonaldTrump) October 5, 2018
Hungary's anti-migrant prime minister Viktor Orban and Donald Trump have both accused Mr Soros of being behind political opposition to them.
Facebook boss Mark Zuckerberg now wants to "reevaluate how we work with communications consultants", Mr Schrage wrote.
"Many people across the company feel uncomfortable finding out about this work," he added.
"Many people on the Communications team feel under attack from the press and even from their colleagues.
"I'm deeply disappointed that so much internal discussion and finger pointing has become public. This is a serious threat to our culture and ability to work together in difficult times."
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Sheryl Sandberg, Facebook's chief operating officer, added in her own post: "It was never anyone's intention to play into an antisemitic narrative against Mr Soros or anyone else.
"Being Jewish is a core part of who I am and our company stands firmly against hate. The idea that our work has been interpreted as antisemitic is abhorrent to me – and deeply personal."