GUWAHATI: Relatives of at least 15 Indian miners trapped in a "rat-hole" mine for 18 days said on Monday they have given up hope that any of them would be found alive, even as rescue operations were stepped up.

"We want his body back so that we can give him a decent burial," said the uncle of 26-year old Omar Ali, who is among those trapped in the mine.

The miners were trapped on Dec. 13, when an illegal mine in India's northeastern Meghalaya state, was flooded.

Thousands of workers, including children, have been killed in so-called rat-hole mining, which involves miners crawling into narrow shafts on bamboo ladders to mine for low-quality coal, in Meghalaya.

The state banned such unregulated mining in 2014 but it still goes on in some places.

A survivor of the disaster, Sayeb Ali, 24, said he too thought there was little chance of anyone coming out alive.

He said 17 miners were trapped in the accident. It was not clear why his figure differed from the government account of 15 miners.

Sayeb Ali said he has survived as he was not deep inside the very narrow mine shaft when disaster struck.

"The people who were digging coal went deep inside and cart-pullers like me and the other four who survived were about eight to 10 feet inside," Sayeb Ali, who is not related to Omar Ali, told Reuters by telephone.

India is one of the world's most dangerous countries to be a coal miner, with one miner dying every six days on average in 2017, according to government data.

Government officials said on Monday rescuers have only been able to find three helmets and two axes underground.

Officials said the navy on Sunday sent 15 divers with cameras and specialist equipment into the mine in an attempt to reach the bottom of the pit, but they had found nothing.

"The problem is there is murky water that entered the rat-hole pit from a nearby river," Santosh Kumar Singh, an official with the National Disaster Response Force, told Reuters.