A total of 50 websites are in the midst of being probed and shut down by the Chinese authorities for spreading rumours, publishing unverified information online and creating panic over the Tianjin blasts.

Eighteen of them would be shut down and their licences suspended, while the rest would be temporarily closed for a month as they had caused negative influences, said the Cyberspace Administration of China (CAC) in a statement posted on its official website.

It pointed out that the “punished” websites had spread rumours such as “Tianjin blast casualties hit at least 1,000 people”, “Tianjin has turned chaotic, shopping complexes robbed”, “Tianjin's top leadership has been reshuffled”.

The CAC claimed that the public had lodged reports and complaints on the relevant rumours which were being disseminated via China's Twitter-like Weibo, mobile app Wechat.

Netizens expressed disbelief over the official number of casualties released by the authorities after the two powerful explosions struck the Chinese port city about 11.30pm Wednesday.

As of Saturday morning, Tianjin's publicity department had confirmed that 112 people were killed in the blasts, including 85 firefighters, Xinhua news agency reported.

The news agency said 95 people remained missing, while 722 others remained in the hospital, with 58 in critical condition.

Xinhua said Chinese President Xi Jinping had noted that profound lessons should be learned from the incident, while China Daily reported Premier Li Keqiang had visited the scene on Sunday, on behalf of the president, to offer condolences to the firefighters, the victims and their families.

Nuclear and chemical experts were dispatched to the blasts site to locate and measure the area contaminated by sodium cyanide, an inorganic compound which will release the highly toxic gas of hydrogen cyanide, while thousands of residents had been evacuated.

The cause of the blasts remain unclear.