Up to seven coal miners were killed and as many as 40 more were missing, feared dead, after a massive explosion and collapse at a mine in Indonesia on Tuesday, police and officials said.
Emergency workers were frantically searching for survivors amid fears most had died because the illegal mine in Sawah Lunto district, West Sumatra province had no ventilation and poor safety standards, officials said.
"It's been more than four hours since they were trapped inside the hole. I don't think we can save them as there was zero ventilation in there," provincial disaster management chief Ade Edward told AFP.
Police said methane gas ignited in the mine, causing a massive explosion that left a crater about 100 metres (330 feet) deep.
"We've pulled out seven bodies so far and 24 people are still trapped inside," police officer Jasman told ElShinta radio.
Numbers of dead and missing varied. Senior health ministry crisis official Rustam Pakaya said five people had been killed, 40 were missing and nine had been injured.
The mine was owned by a group of residents and the miners were using traditional methods, with little or none of the mining safety measures required by law in most countries, Edward said.
"According to witnesses there was an explosion caused by methane gas. Methane gas is the main threat to local miners and there have been several explosions before," he added.
The blast was heard 1.5 kilometres (about a mile) away and sent flames 50 metres into the air, local government official Syafriwal told ElShinta.
Some of the survivors were severely burned, hospital staff said.
"Two are in very critical condition, with 40 percent and 70 percent burns respectively. The skin on their body is peeling all over," said doctor Antony Kurniawan, from Sawah Lunto city hospital.
"One died... his whole body was charred from the explosion."
Twenty rescue workers had entered the collapsed mine shaft with specialised equipment including oxygen tanks, disaster response official Adriyusman said from the scene.
But he said there was little hope anyone else would be found alive.
"I'm pessimistic that anyone will survive because their bodies might have been completely incinerated in the explosion," he said.