Facebook has removed more than three billion fake accounts from October to March, twice as many as in the previous six months.
Nearly all of them were caught before they had a chance to become "active" users of the social network, the company says.
In a new report, Facebook said it saw a steep increase in the creation of abusive, fake accounts.
While most of these fake accounts were blocked "within minutes" of their creation, the company said this increase of "automated attacks" by bad actors meant not only that it caught more of the fake accounts, but that more of them slipped through the cracks.
As a result, the company estimates that five per cent of its 2.4 billion monthly active users are fake accounts, or about 119 million.
This is up from an estimated three to four per cent in the previous six-month report.
The increase shows the challenges Facebook faces in removing accounts created by computers to spread spam, fake news and other objectionable material.
Even as Facebook's detection tools get better, so do the efforts by the creators of these fake accounts.
The new numbers come as the company grapples with challenge after challenge, ranging from fake news to Facebook's role in elections interference, hate speech and incitement to violence in the US, Myanmar, India and elsewhere.
Facebook also said on Thursday it removed more than seven million posts, photos and other material because it violated its rules against hate speech.
Australian Associated Press