China's three top social media platforms said they felt "deep regret" and would "fully cooperate with the investigation" and "take active rectification and reform", following Friday's government probe into their cyber-security violation.

With users on these three platforms "spreading violence, terror, false rumors, pornography and other hazards to national security, public safety and social order", Baidu's forum site Tieba, Tencent's WeChat and Sina's Weibo were suspected in breach of cyber-security law, failing to fulfill their responsibility to censor illegal contents posted by their users, said the Cyberspace Administration of China (CAC).

Baidu Tieba first responded to the investigation result on Friday, expressing its deep regret and willingness to actively cooperate with government departments to rectify the problem, saying it would also strengthen its auditing intensity to keep illegal and harmful information out.  

Tieba said it has always committed to constructing a law-abiding and harmonious network community with its users. It has invested a lot of manpower and resources to audit and deal with illegal information while some still slipped through supervision. It felt deeply sorry for the trouble it brought to users.

WeChat and Weibo also made response later the same day.

The WeChat team said they did serious self-inspection and rectification, and would actively cooperate with the CAC's Guangdong office on the investigation.

The team also said they had taken measures, of both technologies and regulations, to cope with illegal information which is an abomination for both WeChat and the public, calling for the users to comply with relevant laws and regulations to fight against illegal information and build a healthy and secure network environment together.

Weibo said it would face up to the issue, and actively cooperate with CAC's Beijing office on the investigation. It would also take active rectification and strictly implement the corporate's responsibility into work, taking Cyber-security Law as the guidance for operating the platform.

Being aware of its role and responsibility, Weibo said it would keep upgrading supervision measures via innovation of its products, technologies and operation, resolutely cracking down illegal information.

It also encouraged netizens to report illegal contents to the platform and would intensify its handling over the reported contents, establishing a clear, healthy and orderly network for the public.

The CAC has developed the investigation on the issue and will release the follow-ups.