Five people remain in hospital Sunday following a failed fireworks display attended by hundreds of thousands of spectators at Hangzhou's icon West Lake in East China's Zhejiang Province Saturday night.

Two fireworks shells misfired and landed among onlookers injuring 151, most of whom suffered minor skin burns and damage to their clothing.

The fireworks display, celebrating the opening of the 14th West Lake International Expo, started at 7:45 pm.

The explosions, which happened some 20 minutes later, lasted for some 30 seconds, a witness surnamed Xu told the China News Service.

Those who remain hospitalized suffered injuries to their legs, face, back or ears. The injured were treated at the nearby Affiliated Hospital of Hangzhou Normal University.

"The firework was fired from a platform on the lake, but instead of going up in the air it went toward the audience and exploded," a witness surnamed Qiu told the Guangzhou-based Nanfang Daily.

The fireworks show continued for a while after the accident, reported the Shanghai-based Oriental Morning Post.

Some people in the audience were shocked that many of the on-duty police officers were cadets and seemed not well-trained to handle such an emergency.

The government of Gongshu district in the city apologized in a statement late Saturday, while the city's government promised in another statement Sunday that it will compensate the injured.

The authorities also said the results of their investigation will be made public when it is completed.

Fireworks displays have traditionally signaled the opening of the West Lake International Expo. This year 150,000 fireworks were launched from three venues around the icon West Lake.

The accident occurred near the Grand Canal.

According to fireworks regulations in Hangzhou, event organizers must apply for a permit and police are required to verify the qualifications of the company and personnel involved.

Police are also charged with supervising and coordinating security and emergencies during the event.

Setting off fireworks at events without authorization is punishable by fines ranging from 10,000 yuan ($1,596) to 50,000 yuan, said the regulation.

Hangzhou's West Lake was named a World Cultural Heritage site last year.