An explosion at a restaurant in the northwestern Chinese city of Yinchuan has left at least 31 people dead, state media reported Thursday.

Seven additional people were receiving "all-out rescue treatment" for burns and cuts from broken glass, according to the state-operated Xinhua news agency.

Nine people including a restaurant owner are being held by police following the blast, state media said.

"In accordance with the law, public security organs have held nine people, including the barbecue restaurant owner, shareholders and staff... and frozen their assets," state broadcaster CCTV reported, citing the regional Communist Party committee.

What we know about the explosion

The blast occurred at around 8:40 p.m. local time at a barbeque restaurant on a busy street in the capital of the traditionally Muslim Ningxia Hui Autonomous Region.

It was caused by "a leak of liquefied petroleum gas," Xinhua reported, citing the regional Communist Party committee.

People were gathering for the start of the three-day Dragon Boat Festival holiday.

The Ministry of Emergency Management said local fire and rescue services had deployed more than 100 people and 20 vehicles to the scene.

State broadcaster CCTV showed visuals of more than a dozen firefighters working at the site as smoke billowed out of a huge hole in the restaurant's facade.

The footage also showed glass shards and other debris littered on the street. 

Chinese President Xi Jinping told authorities to go all out to treat the wounded and said safety supervision in key sectors should be strengthened, CCTV reported.

Safety issues

China regularly witnesses such types of industrial accidents, usually attributed to poor government supervision, corruption, cost-cutting measures by employers and little safety training for employees.

During the Asian nation's May Day holiday, at least nine people were killed in a blast at a petrochemical plant.

In 2015, a series of explosions in the northern port city of Tianjin left 173 people dead.

dvv/rt (AFP, AP, Reuters)