At least 15 people have been killed and another 20 remain missing after a gas explosion in a coal mine in south-west China. 

Out of the 35 miners, two were rescued after the explosion on the morning of 31 October, local time.

This coal mine is operated by Jinshangou Coal Industry in the city of Chongqing.

Currently, rescue works are underway at the site and municipal authorities have ordered the suspension of operations in all small coal mines in the city pending new safety inspections. 

"We are still working all-out to search for the 20 missing miners."

A team of China’s State Administration of Work Safety reached the mine to investigate and monitor the rescue operations.

The potential cause for this explosion has not yet been determined.

Chongqing Deputy Mayor Ma Huaping was quoted by BBC as saying: "We are still working all-out to search for the 20 missing miners, and will exert our utmost as long as there's still a ray of hope."

China is the largest producer of coal in the world.

Most of the coal mines do not operate under safe conditions. Despite regulatory authorities having tightened safety measures, accidents are still common.

Earlier this year, four people were rescued after a gypsum mine collapsed in Shandong province. The four miners were trapped underground for 36 days.