A gas explosion at a Siberian colliery has killed at least 20 miners and left 25 others missing. Rescue teams are searching a vast shaft for the missing men.
A spokesman for Siberia's Kemerovo district - heart of the Kuzbass coalfield where accidents are a regular occurrence - said rescuers had brought 20 bodies to the surface more than 12 hours after the accident.
"There was a big explosion and then a serious collapse of the shaft's walls. Both the electrical and ventilation systems failed," Sergei Cheremnov said by telephone.
"We are still looking for 25 miners."
Six miners scrambled out of the Taizhina mine in the town of Osinniki after the gas leak occurred at about 6.30 a.m. Three were pulled free with serious burns.
The missing miners were believed to be trapped 700 metres below the surface. No contact had been established with them, officials said.
A local official had earlier said the accident was caused by "a release of methane".
Kemerovo's high-profile governor Aman Tuleyev, shown on television coordinating rescue efforts, said teams were making their way towards the trapped miners by both a direct route and a five km detour through a nearby mineshaft.
Television showed dejected miners outside the main shaft who had been due to take over on the morning shift. Distraught relatives waited for news in an auditorium.
Russia 's coal mines are plagued by accidents generally blamed on lax operating procedures and old equipment.
Mining accidents are even more frequent in neighbouring Ukraine's Donbass coalfield, where some collieries date from the 19th century.