Facebook has admitted that tens of millions – up to 4% – of active accounts over the last six months were fake.
The admission comes alongside newly published data on Facebook's content removals – which the company has released for the first time – revealing the amount of abuse which occurs on its site.
The company estimated that around 3% to 4% of the active Facebook accounts on the site during this time period – roughly 43 million out 2.19 billion – were fake.
All in all the company removed 583 million fake accounts, although these were not all active at the same time.
The figures show how much graphic violence, adult nudity and sexual activity, terrorist propaganda, hate speech, spam, and fake accounts that are uploaded to its platform.
The company stated that between October 2017 and March 2018 it took down or put warning labels on:
:: 837 million pieces of spam
:: 583 million fake accounts
:: 21 million pieces of adult nudity and sexual activity
:: 3.5 million pieces of violent content
:: 2.5 million pieces of hate speech
Explaining the figures, the company's vice president of product management Guy Rosen said: "It's important to stress that this is very much a work in progress and we will likely change our methodology as we learn more about what's important and what works."
The high numbers of spam that the company reported were caught by Facebook's internal tools, the company said, and relied on taking down the fake accounts which spread it.
Many of these accounts were "disabled within minutes of registration" according to the company, although it provided only surface-level figures on the total number of accounts banned.
Mr Rosen added: "We believe that increased transparency tends to lead to increased accountability and responsibility over time, and publishing this information will push us to improve more quickly too.
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"This is the same data we use to measure our progress internally – and you can now see it to judge our progress for yourselves. We look forward to your feedback."
Such feedback will be on the way from the House of Commons, where an inquiry has again criticised Facebook for failing to answer its questions about how the company handles UK citizens' data.