Facebook Inc admitted on Tuesday that the company needs to improve how it handles hate speech across its platform, following pressure from campaign groups and advertisers.

In a blog post by its safety team, the company acknowledged there had been problems with removing content that would be considered examples of gender-based hate. "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," the company said in the post.

An open letter from several feminist groups urged Facebook to ban pages that they said promoted violence. The letter highlighted Facebook pages with names like "Violently Raping Your Friend Just for Laughs" and "Kicking your Girlfriend in the Fanny because she won't make you a Sandwich," and other pages that included graphic images of women being abused.

The activists sent over than 5,000 e-mails to Facebook's advertisers and elicited more than 60,000 posts on Twitter. Facebook's backlash was enough to provoke also provoked Nissan and more than a dozen smaller companies to say that they would withdraw advertising from the popular social-networking site.

The company said it would begin rolling out changes immediately after it became "clear that our systems to identify and remove hate speech have failed to work as effectively as we would like".

Marne Levine, Facebook's vice president of Global Public Policy, said in the post: "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 In other cases, content that should be removed has not been or has been evaluated using outdated criteria."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," Levine added