MOSCOW :Smoke at a coal mine in Russia's Kemerovo Region claimed the lives of 52 people, including six rescuers. It was the country's deadliest mine catastrophe in five years. According to early data, there were no survivors in the Listvyazhnaya mine, according to TASS, with the majority of the dead remaining underground and being brought to the surface when temperature and methane concentration permit. On Thursday, 11 miners were killed at a depth of 250 metres due to the igniting of coal dust in the ventilation system and the resulting smoke. According to regional authorities, 38 persons were admitted to hospitals, four of them were in critical condition, and another 13 were treated as outpatients. When the catastrophe occurred, there were 285 individuals underground, and the majority of them were hauled out of the mine. Russian President Vladimir Putin sent his "heartfelt condolences" to the bereaved families. From Friday to Sunday, the Kemerovo Region will observe three days of sorrow. Four people killed in explosions in Afghanistan: official Report Pakistani police detain four people for blasphemy Ukraine will not launch military offensive in Donbas: FM