Twelve people have been “formally detained” in China after the massive explosions in Tianjin earlier this month.

Among them are the chairman, vice-chairman and three deputy general managers of the company that owned the warehouse containing dangerous chemicals.

On top of the arrests 11 officials and port executives have been accused of dereliction of duty or abuse of power.

News of the detentions comes a day after the head of China’s work safety regulator, Yang Dongliang, was suspended for corruption.

He was also a former vice mayor of Tianjin.

The state prosecutor said officials from a range of agencies, including Tianjin’s land resources, work safety and customs offices have been irresponsible and negligent.

China’s state-run Xinhua news agency says 139 people were killed in the blasts, 84 of them were fire fighters.

Meanwhile 34 people remain missing.

Of the 700 who were reportedly injured in the blasts 527 are still in hospital.