At least 17 people have been killed by an explosion in an Indonesian coal mine, with 23 people still trapped, officials have said.

Rescuers working overnight pulled eight bodies from the mine in West Sumatra province, which collapsed after an explosion of methane gas on Tuesday.

Ade Edward, the provincial disaster management chief, told AFP news agency: "There's a large chance that [those trapped are] already dead because there's a lot of carbon dioxide there."

The blast at the mine in Sawah Lunto district sent flames 50m into the air and left a huge crater on the surface, officials said.

Adriyusman, a disaster response official, also said that a dangerous concentration of methane gas was hampering efforts by rescuers to get to the miners trapped about 100m underground.

The miners were said to be using traditional methods with few modern safety measures in place.

According to the World Coal Institute, Indonesia has the largest coal reserves in the Asia-Pacific region behind Australia, India and China.

It is the world's second-largest coal exporter after Australia.