Facebook says it deleted or added warnings to about 29 million posts that broke its rules on hate speech, graphic violence, terrorism and sex, over the first three months of the year.
It is the first time that the firm has published figures detailing the scale of efforts to enforce its rules.
Facebook is developing artificial intelligence tools to support the work of its 17,000 human moderators.
But the report suggest the software struggles to spot some types of abuse.
For example, the algorithms only flagged 38% of identified hate speech posts over the period, meaning 62% were only addressed because users had reported them.
By contrast, the firm said its tools spotted 99.5% of detected propaganda posted in support of Islamic State, Al-Qaeda and other affiliated groups, leaving only 0.5% to the public.
The figures also reveal that Facebook believes users were more likely to have experienced graphic violence and adult nudity via its service over the January-to-March quarter than the prior three months.
But it said it had yet to develop a way to judge if this was also true of hate speech and terrorist propaganda.
“As we learn about the right way to do this, we will improve the methodology,” commented Facebook’s head of product management, Guy Rosen.
On the latter, the company estimates about 3% to 4% of all active users on Facebook are fake, and said it had taken 583 million fake accounts down between January and March.
The figures indicate graphic violence spiked massively – up 183% between each of the two time periods in the report.
It said that a mix of better detection technology and an escalation in the Syrian conflict might account for this.