Companies including Google, Facebook and Twitter could face European Union laws forcing them to be more proactive in removing illegal content if they do not do more to police what is available on the internet.
The European Union executive outlined in draft guidelines how internet firms should step up efforts with measures such as establishing trusted flaggers and taking voluntary measures to detect and remove illegal content.
Proliferating illegal content, whether because it infringes copyright or incites terrorism, has sparked heated debate in Europe between those who want online platforms to do more to tackle it and those who fear it could impinge on free speech.