Police said today 29 people, including two Britons, were believed to be dead after a second blast inside the New Zealand mine where they were trapped.
Police superintendent Gary Knowles said the second explosion occurred Wednesday afternoon, local time.
Potentially explosive methane gas had been swirling in the Pike River mine since the initial blast last Friday.
That danger had kept rescuers from entering the mine on the South Island.
"Today there was another massive explosion underground and based on that explosion no-one would have survived," said Supt Knowles, heading the rescue operation.
"We are now in recovery mode."
Pete Rodger, 40, from Perthshire, and Malcolm Campbell, 25, from St Andrews, Fife, were among the missing miners.
Rescuers had become increasingly pessimistic about the chances of pulling the men from the network of tunnels one and a half miles deep in the side of a mountain, following Friday's powerful explosion at the mine, near Greymouth.
A drilling team which yesterday broke through to the section of mine where the men were working was greeted by a blast of potentially deadly gases.
Hot air and gas rushed the hole when the chamber roof was punctured and Pike River Coal chief Peter Whittall said initial tests showed it was "extremely high in carbon monoxide, very high in methane and fairly low in oxygen".
Carbon monoxide - the polluting gas from car exhausts - is extremely poisonous, while explosive methane is the gas believed to have ignited on Friday.
New Zealand's prime minister John Key had warned the nation to prepare for the worst as frustration grew among some relatives of the missing.
Security footage of Friday's blast showed a wall of white dust surging from the mine entrance and small stones rolling past for about 50 seconds as the force of the explosion ripped out of the mine. The dust was blown across a valley and the blast wave shot up a ventilation shaft, tearing off surface vents hundreds of feet above.
New Zealand's mines have been safe historically, with 181 deaths in 114 years. The worst disaster was in 1896, when 65 died in a gas explosion. Friday's explosion occurred in the same coal seam.