The death toll from a powerful explosion in an Internet cafe in southwest China has risen to seven, state media said Sunday, as officials ordered a nationwide safety inspection of entertainment venues.

The blast -- thought to have been caused by chemicals -- ripped through the web cafe in Kaili city in Guizhou province late Saturday, injuring 37 people and reducing the building to ruins, the official Xinhua news agency said.

The death toll reached seven after a woman died from severe burns on Sunday afternoon, it said.

The other injured people were still being treated in local hospitals.

In response to the blast, the Ministry of Culture ordered relevant departments and bureaus to "take immediate concrete measures and carry out nationwide safety inspections of cultural venues."

The explosion was triggered by chemicals including sodium nitrite and aluminium chloride "illegally stored" next door to the Internet cafe, Xinhua said, citing local police.

Police have detained one person for "illegally possessing the chemicals" while the cafe's boss and manager have been taken into custody for questioning, the report said.

At least 45 people were inside the cafe at the time of the blast.

State television showed rescue workers pulling victims from the devastated building and rushing the injured to hospital.