Facebook has said it will not allow horrific self-harm images to be posted on its social media platform while stressing its policies on content involving suicide practices, following mounting criticism of social media companies over how to curb violent content.

Facebook also revealed Tuesday that searching for content related to self-harm will now be more difficult for Instagram, and will ensure that it does not appear in the recommended materials in the "Explore" section of the image sharing application.

The Facebook statement on World Suicide Prevention Day follows comments from Twitter that self-harm content would not be labeled as offensive, in an effort to reduce the stigma surrounding suicide.

About eight million people commit suicide every year or one every 40 seconds, according to a WHO report.