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The Office for Cyberspace Administration said the three platforms had failed to monitor content on their sites, reports the BBC.
It said people had been using the platforms to spread terrorism-related material, rumours and obscenities.
The breaches "jeopardised national security", the administration said.
Last month 60 popular celebrity gossip sites were closed overnight for corrupting "core socialist values", and a new regulation released in May requires all online news portals to be managed by Communist Party sanctioned editorial staff, according to the Cyberspace Administration.
The authorities in China heavily censor the internet, routinely blocking content or search terms and removing posts they consider sensitive, the BBC reported.
Search engines like Google are blocked, and access to many foreign media outlets is restricted too.