LONDON (Reuters) - A gunman who killed 49 people at two New Zealand mosques live-streamed the attacks on Facebook for 17 minutes using an app designed for extreme sports enthusiasts, with copies still being shared on social media hours later.

The live footage of Friday's attacks, New Zealand's worst-ever mass shooting, was first posted to Facebook and has since been shared on Twitter, Alphabet Inc's YouTube and Facebook-owned Whatsapp and Instagram.