Leaders and tech firms pledge to tackle extremist violence online

Jacinda Ardern and Emmanuel Macron host Christchurch Call summit in Paris

World leaders and heads of global technology companies have pledged at a Paris summit to tackle terrorist and extremist violence online in what they described as an "unprecedented agreement".

Wednesday's event, two months to the day since the Christchurch massacre in New Zealand, drew up a "plan of action" to be adopted by countries and companies to prevent extreme material from going viral on the internet.