Facebook has pledged to "do better" after thousands of people demanded it remove pictures, groups and videos from its site which promote violence against women.
Activists said that the social network was refusing to take down material which they said glorifies rape and domestic violence.
While Facebook had already said that there was "no place" on its site "for hate speech or content that is threatening, or incites violence", several examples collected on the website Women Action Media appeared to show its moderators turning down requests to remove offensive pictures.
One image highlighted on the website, which was apparently live despite multiple takedown requests, showed a woman lying in a pool of blood with the slogan "I like her for her brains".
Now, after a coalition of groups including the UK-based Everyday Sexism Project, WAM and around 40 other groups called on the social network to go further and revise its policies, and more than 220,000 people signed a petition, the social network has responded with a promise to look again at how it decides which pictures to moderate.
Facebook said on its website:
"In recent days, it has become clear that our systems to identify and remove hate speech have failed to work as effectively as we would like, particularly around issues of gender-based hate.
"In some cases, content is not being removed as quickly as we want. In other cases, content that should be removed has not been or has been evaluated using outdated criteria. We have been working over the past several months to improve our systems to respond to reports of violations, but the guidelines used by these systems have failed to capture all the content that violates our standards.
We need to do better - and we will."
Facebook said it would review and update the guidelines for its moderators, would retrain teams that evaluate reports of hate speech, and would try to hold creators of "cruel or insensitive content" to publish it using their real identity.
WAM said that Facebook's statement was an "important commitment" and said it had been invited to take part in an "ongoing conversation" about hate speech on the site.
Jaclyn Friedman, executive director of WAM, said in a statement:
"We are reaching an international tipping point in attitudes towards rape and violence against women. We hope that this effort stands as a testament to the power of collaborative action."