At least 31 people are dead and seven injured in the Chinese city of Yinchuan, in northwest Ningxia region, after a gas explosion at a barbecue restaurant Wednesday night, according to state media.

The explosion was caused by a leak of a liquified gas tank inside the restaurant, and took place around 8:40 p.m., according to state broadcaster CCTV.

Among the seven injured, one person is still in critical condition. The other six are being treated in the hospital for minor injuries, burns and glass cuts.

Chinese leader Xi Jinping has issued instructions to authorities on the scene, requiring "all efforts" to treat the injured, strengthen safety supervision and protect residents' safety, according to CCTV.

The restaurant is located on a busy street, state media reported. The incident came just before China began its three-day national public holiday, from Thursday to Saturday, marking Dragon Boat Festival.