The Cyberspace Administration of China said it is probing Baidu Inc.'s forum site Tieba, Tencent Holdings Ltd.'s WeChat and SINA Corp. unit Weibo Corp. for allegedly violating the country's cybersecurity laws.

The watchdog said users of the three social media sites are "spreading violence, terror, false rumors, pornography and other hazards to national security, public safety, social order," Reuters reported Aug. 11.

China has adopted a tougher stance on censorship by implementing strict laws that ban content that is violent, obscene or deemed offensive to the Communist Party of China. It has also required state-run telcos to block access to virtual private networks that can dodge censorship restrictions.

Furthermore, China is cracking down on live streams that "undermine national security" and "destabilize society." It has ordered the closure of 10 live streaming platforms and issued fines on 48 companies for streaming illegal content. Microblogging site Sina Weibo and two other platforms have also been ordered to stop audio- and video-streaming services.