On Saturday, rescuers lifted 33 miners to safety from tunnels 800 metres below ground at the Zapadnaya coal mine in Russia's Rostov region. They had been trapped for nearly two days.
The rescue operation was halted late on Saturday as gas was discovered in the tunnel where rescuers were working and all rescuers were lifted to the surface, officials said.
"The operation has become dangerous because of the gas. We have decided to lift the rescuers to the surface," said a spokesman for the Rostov region governor.
Two rescuers were intoxicated with gas, an official with the emergencies ministry said.
The rescue operation was to resume on Sunday at 0500GMT, officials said.
In all, 71 miners were working in Zapadnaya's shafts when numbing water first rushed in. Twenty-five scrambled to the surface right away; on Saturday morning rescuers located a group of 33, but nothing has been heard from the second group of 13.
The miners - exhausted, soaked, their faces blackened – were hoisted in a service lift, a handful at a time, to emerge to crowds of straining, anxious relatives.
Wives pushed forward to see the men's faces and as some broke into smiles and sighs of relief, others broke down in tears.
Anxious relatives wait at the mine
entrance for news of those trapped
The miners were immediately taken to hospital by ambulance.
Several were suffering from hypothermia, while others were said to be in good shape.
"The miners are not in a life threatening condition, their condition is satisfactory," said Dmitry Burtsev, the senior doctor at the hospital of Novoshakhtinsk, where the mine is located.
"Some are suffering from hypothermia, but they are all calm," he added.
Authorities prevented the rescued men from speaking to their relatives before arriving at the hospital, where access was severely restricted. Families had to talk to prosecutors before seeing their loved ones.
The names of those rescued were not released either to the media or to relatives waiting near the pit entrance for news.
Hope and pessimism
Sergei Nazarov, deputy to Vladimir Chub, the Rostov region governor, said that "for the moment we must suppose they are alive, the search is continuing and there is a
chance we can save them."
Upon emerging, several of the rescued miners told reporters they were pessimistic about the chances of the 13, who had probably taken a wrong turn in the mine's winding tunnels.
Several miners speculated that the larger group had succeeded in staying alive by entering the mine's main shaft from where they were able to telephone rescuers, but that the second group of 13 headed for a pocket about a kilometre and a half away.
A retired miner at the scene said he was reminded of the August 2000 Kursk submarine disaster in which 118 seamen died: "we just have rumours - now they are alive, now they're not."
"We wouldn't have this mess if people weren't cutting back on safety measures"
A miner who gave his name as Vladimir, criticised the mine's managers: "We wouldn't have this mess if people weren't cutting back on safety measures. Everyone knew the water was building up nearby, but it hadn't been pumped out since 1999."
Mines in Russia are notorious for their poor safety record, and fatal accidents are common.
The accident was the second at Novoshakhtinsk this year. Water flooded the mine in February, but there were no people underground at the time.