The bodies of three workers were retrieved from a 300-foot deep flooded coal mine in Assam’s Umrangso district on Saturday, on the sixth day of rescue operations, reported India Today. Five others are still trapped underground.

Those whose bodies were recovered on Saturday have been identified as 27-year-old Lijen Magar, a resident of Umrangso, 57-year-old Khushi Mohan Rai from Fakiragram and 37-year-old Sarat Goyari hailing from Thailapara, according to The Hindu.

At least four workers have died in the illegal rat-hole mine since Monday, when the miners accidentally breached a sub-surface water source, flooding the shaft and leaving them with little time to escape.

Army divers had on Wednesday recovered the body of Ganga Bahadur Srestho from Udayapur district of Nepal.

The rescue operations got a boost on Friday when water levels in the mine receded by about 23 feet. This came after three abandoned mines within 500 metres of the accident site were drained using pumps, reducing the height of the region’s water table.

Officials from the Indian Army, Navy, the National Disaster Response Force, the State Disaster Response Force, the Oil and Natural Gas Corporation, Coal India and the district administration are collaborating on the rescue operation.

On Saturday, the rescuers were installing a heavy-pressure pump that was flown in by Coal India Limited from Maharashtra’s Nagpur on Thursday, The Hindu reported. The machine can extract as many as 500 gallons of water per minute.

National Disaster Response Force official Kuldeep Sharma said that the workers were in the rat-holes connected to the central pit of the mine when it got flooded.

Rat-hole mining has been banned in India since 2014. It is considered to be an unscientific and dangerous technique in which workers enter deep tunnels around three or four feet high to extract coal. However, several instances of the practice have since been recorded across the North East, including in Assam.

The Assam Police has so far arrested two individuals in connection with the case. One of them, Hannan Laskar, has been accused of investing in the mining operation and pressuring the workers to extract large quantities of coal. The other, Punish Nunisia, is alleged to be the leaseholder of the mine.

Congress MP Gaurav Gogoi on Saturday wrote to Prime Minister Narendra Modi requesting the formation of a Special Investigation Team to investigate the incident.

“Illegal mining continues unchecked in Assam, fuelled by weak law enforcement and local complicity," Gogoi said in his letter, reported PTI. “Those responsible for this tragedy must be held accountable. Moreover, broader issues of safety, corruption and environmental harm need to be addressed too.”