At least 18 people died on Thursday after an explosion ripped through an illegal coal mine in the north-eastern Indian state of Meghalaya, officials said.

"During the course of the rescue operation, a total of 18 dead bodies have been recovered from the site of the explosion," local police said in a statement.

Eight other people were injured, said Manish Kumar, top official in East Jaintia Hills district where the explosion happened.

Rescuers were digging through the rubble at the site to find out if more miners were trapped inside but the operations halted at sundown.

Kumar said it was an "illegal rat-hole mine" and that authorities were awaiting personnel from state and federal disaster management agencies to resume the search on Friday morning.

Rat-hole mines are deep vertical shafts dug mostly into hillsides that branch out into narrow tunnels to reach and retrieve coal and other minerals.

A federal environment court banned rat-hole mining in Meghalaya in 2014 after local communities complained it was polluting water sources and putting lives at risk.

But it's still widely practised across the state, especially in the East Jaintia Hills.

District police chief Vikash Kumar said the explosion was likely due to a dynamite blast but added that further forensic investigation was underway.

"After the explosion, a fire happened. Lots of toxic gas has accumulated," Vikash Kumar said.

Meghalaya chief minister Conrad K Sangma said a "comprehensive inquiry" had been ordered into the incident and promised accountability.

Prime Minister Narendra Modi said he was "pained by the mishap."

"Condolences to those who lost their loved ones. May the injured recover at the earliest," he said in a statement on social media.

The families of the deceased would receive 200,000 rupees compensation, the statement said. (AFP)