According to the Xinhua News Agency, the escalator which malfunctioned on Tuesday leaving one dead and 30 injured in Beijing, has flaws in its design and manufacture, and its producer Otis should be held accountable, local authorities said Thursday.

A wounded woman receives medical treatment at the Peking University People's Hospital after an accident happened in the Beijing Zoo Station of Subway Line 4 in downtown Beijing, capital of China, July 5, 2011.

The accident happened Tuesday morning when a rising escalator, type Otis 513 MPE, suddenly changed its direction at the A exit of the Zoo Station on Line 4 subway.

An initial investigation shows that the accident was caused by flaws in Otis's design and manufacture. It also had something to do with the fact that the producer's maintenance was not thorough enough, said Zhang Juming, deputy chief of the municipal Quality and Technical Supervision Bureau.

The accident happened when a component malfunction led to the sudden loosening of the escalator's drive chain, according to a statement released by the municipal Quality and Technical Supervision Bureau Wednesday.

The escalator's protection mechanism that was supposed to prevent such a sudden backward movement did not work, said a spokesman of Beijing Municipal Commission of Transport on Wednesday.

According to Yang Ling, a spokeswoman with the subway operator Beijing MTR Corporation, the escalator was still in its guarantee period. The manufacturer completed a routine check on June 22, she added.

The General Administration of Quality Supervision, Inspection and Quarantine has asked all the users of Otis 513 MPE escalators in China to suspend the escalator's operation and have the producer to check them before they can be reused, Zhang said.

The 25 people who suffered slight injuries have been discharged, and the other five people are recovering, said Li Xiaosong, deputy chief of Beijing Municipal Commission of Transport.

Last year, loose bolts caused an escalator at a Metro station in Shenzhen, south China's Guangdong Province, to reverse, injuring 25 people.