Stacks of illegally stored chemicals in a shop exploded late Saturday night in a southwest Chinese city, leaving seven killed and 37 injured, including eight severely, in an adjacent Internet cafe next door, authorities said Sunday.

Firefighters work at the scene where six people were killed and 37 others injured in an Internet cafe explosion in Southwest China's Guizhou province Saturday night. [Photo/Xinhua]

 The explosion, caused by sodium nitrite and other explosive chemicals, occurred in Kaili City, Qiandongnan Miao-Dong Autonomous Prefecture, Guizhou Province at about 11 p.m., local officials told a press conference.

The blast flattened the shop and ripped through the Internet cafe, which is nestled under a bridge. A fire ensued the explosion.

Six people were killed on site and one woman died of extensive burns after treatment failed Sunday afternoon in hospital, officials said. Forty-five people were in the cafe when the explosion occurred. Only one of them was not injured.

Police have detained Wu Zhanzhi for illegal possession of chemicals. The Internet cafe's boss Chen Chenggui and manager Xing Guangchang, both in their 20s, were also put in police custody.

Meanwhile, the Ministry of Culture, which overseas operations of Internet cafes, ordered a nationwide safety checks of entertainment venues following the blast.

Safety watchdogs should increase the times and frequency of inspection of Internet cafes and other entertainment venues and severely punish violators to ensure these cultural venues' safety, Vice Minister Ouyang Jian said in a circular.

In Kaili, the rescue work ended Sunday. The injured, including 8 seriously, were being treated in local hospitals. A statement from the Kaili municipal government said the injured people were in a stable condition.

Long Xianze, deputy head of Qiandongnan Miao-Dong Autonomous Prefecture Hospital, said the seven seriously injured people the hospital admitted were out of danger. The most seriously injured suffered burns over 35 percent of his body.

"I was chatting online when the blast knocked me over. I pushed away a wreaked desk that had landed on me and managed to climb out," said 18-year-old Long Jiuke, who was being treated in the hospital.

"The ceiling fell down after the blast. Someone pushed me down in the chaos, others stamped on me," said a female student of Qiandongnan Prefecture Middle School, who declined to give her name. She had burns on her face.

The investigators are presently identifying the bodies of the dead, one of whom was a child. Xinhua reporters heard that middle school students were among the injured. But it was not immediately clear how many children were among the casualties.

Internet cafes are not allowed by law to receive people under 18 years old in China.

The Internet cafe, with 140 computers, had been operating with a license for a number of years when the blast occurred, police said.

A further investigation is underway.

"The location and environment of the Internet cafe is not safe. We will find out who approved its operation and who was in charge of safety supervision. They will be held responsible," said Li Feiyue, head of Qiandongnan Miao-Dong Autonomous Prefecture.