Facebook received tens of thousands of potential "sextortion" and "revenge porn" cases a month, leaked company documents show.
The 100-page handbook Facebook gives to moderators reveals the social network receives swathes of reports regarding abusive sexual material, an area where they "make most mistakes", the Daily Telegraph reports.
The documents, leaked to the Guardian, show Facebook users reported almost 54,000 incidents of sexual extortion and revenge porn in January, with the company disabling 14,130 accounts as a result. Moderators escalated 33 cases for involving children.
The files also also reveal that Facebook will not delete videos and images depicting violence, self-harm and child abuse of a non-sexual nature, since they may draw attention to mental illness or be newsworthy. In some cases, it allows footage portraying physical bullying of children under 7.
Recent changes suggest Facebook has only started to ban abusive posts about disabled people and those with serious health conditions in the last few months.
Revenge porn, which involves intimate images being shared online after a relationship ends, has been a criminal act in the UK since 2015. Offenders face up to two years in prison if convicted of sharing "private, sexual images of someone without consent and with the intent to cause distress".
It is not clear how many cases Facebook passed to the police. The figures for sextortion and revenge porn, which Facebook deems as serious as child exploitation and terrorism, are international and only reflect incidents that have been reported by users. The scale of the problem could be significantly greater if there are a large number of cases not reported.
A source admitted Facebook moderators find it difficult to police sextortion and revenge porn material, "Sexual policy is the one where moderators make the most mistakes," an unnamed source told the Guardian. "It is very complex."
Facebook has been criticised numerous times for censoring posts that it deems to be of a sexual nature that are in fact newsworthy or harmless.
It recently updated its policies after an outcry when it deleted a post containing the Pulitzer prize-winning "Napalm girl" photo posted by Norwegian newspaper Aftenposten.
It has also reinstated images of mothers breastfeeding and virile works of art, claiming to have removed them mistakenly.