Microsoft president and chief legal officer Brad Smith called for stronger tech industry content moderation after videos of a mass shooting in New Zealand went viral online.

In a blog post Sunday, Smith said ”words alone are not enough” to combat violent and hateful posts on tech platforms. Earlier this month, a gunman killed 50 people at mosques in Christchurch, New Zealand, livestreaming the attack. Platforms scrambled to remove the video, which was shared millions of times in edited versions.