Emergency workers struggled with flooded caverns and flammable gas as they searched Wednesday for three miners missing after a methane blast in a Siberian coal mine that killed at least 107 people.

Meanwhile, relatives filed grimly into a morgue to identify sons and husbands among those killed in Russia's worst mine disaster in a decade.

Emergency officials said water, gas and structural damage in the Ulyanovskaya mine was slowing the search for the missing men, while forensic pathologists said identification was difficult because bodies were badly burned, Russian news agencies reported.

Monday's blast ripped through the mine in the coal-rich Kuznetsk Basin region when about 200 workers were underground.

A total of 93 people made it to the surface safely, but the confirmed death toll reached 107 late Tuesday. Regional officials said a British employee of the British-German mining consultancy IMC was among the dead.

Flags across Russia flew at half-staff, church services were held nationwide and television entertainment programs were canceled on an official day of mourning decreed by President Vladimir Putin for victims of the mine disaster, a nursing home fire that killed 63 people and a weekend plane crash that killed six.

Outside the main morgue in Novokuznetsk, relatives of mine blast victims milled in green tents set up by the Emergency Situations Ministry and staffed with uniformed psychologists. A handful stood in line at the door to the morgue as sunshine gave way to a soft snowfall, waiting to be taken in to identify the dead.

Sixty-three victims had been identified, said Valery Korchagin, spokesman for the Emergency Situations Ministry's regional branch.

The first two funerals were held for victims, Russian news agencies reported.

In the mine, crews were considering using pumps to dry out an area where officials believe the three missing miners were trapped, Emergency Situations Minister Sergei Shoigu said.

Divers sent underground covered 65 feet but were unable to go farther because their path was blocked by rubble, Shoigu said. He said authorities had hoped to wrap up the search early Wednesday, but that it would take "much more time" because of the flooding and gas concentrations.

Shoigu also cautioned that it would be impossible to pinpoint the precise cause of the blast quickly, saying it would take at least two weeks to collect data from instruments in the mine that could help determine what happened.

Nikolai Kultyn, an inspector with federal industrial regulator Rostekhnadzor, said there were no gas monitors where the pocket of methane gas had accumulated. He said the high number of deaths was likely due to the fact that many people were in a small area at the time of the blast.

Regional authorities and the company that operates the mine, Yuzhkuzbassugol, said it would be repaired and opened again, news agencies reported. The company said it could be operating again by July, RIA-Novosti reported.

Labor union officials blamed the explosion in part on quota systems that encourage miners to work faster and dig more coal, potentially leading to errors. Some government officials in the past have accused private companies of cutting corners on safety measures in order to save money.

The blast was the latest to highlight the precarious and hazardous state of Russia's mining industry, which fell into disrepair when government subsidies dried up after the collapse of the Soviet Union in 1991.