Smoke billows from the site of an explosion in Tianjin, August 13, 2015. [Photo/CFP]

China's energy watchdog on Saturday demanded safety checks on facilities and systems that involve dangerous chemicals or explosives following the deadly Tianjin blasts.

Facilities involved include hydrogen generation stations, ammonia producing systems, fuel tanks, warehouses storing volatile chemicals and explosives and coal pulverizing and natural gas systems, according to a notice issued by the National Energy Administration.

The repeated emphasis on work safety followed the massive explosions at a warehouse storing dangerous chemicals in north China's Tianjin city on Wednesday night, killing at least 104 people and injuring more than 720.

The State Council Work Safety Commission on Friday said the blasts revealed a lack of safety awareness among businesses, weak emergency response and poor supervision by authorities.

Earlier a senior Beijing official said the Chinese capital will suspend the production of toxic and explosive chemicals from this week.

Companies producing such volatile chemicals were ordered to stop their business until Sept 6, during which time Beijing will host the World Athletic Championships and a military parade marking the end of World War II, according to Deputy Mayor Zhang Tingkun.

Beijing will also conduct a more comprehensive inspection of the security of the production and storage of dangerous chemicals. Companies failing to meet the standard will be shut down immediately.

"No storage of dangerous chemicals is allowed inside the Third Ring Road of Beijing. The inspection will focus on the suburban districts of Fangshan, Tongzhou and Daxing," said Liu Li, an official from the Beijing Administration of Work Safety.

Other security measures for the same period include barring gas stations from selling gas in canisters and the suspension of fireworks sales.