Rescue teams backed by the Indian army have been using explosives to force their way to the epicenter of a 6.9 magnitude earthquake in the remote state of Sikkim, which has killed at least 80 people.Hundreds of residents in the capital of Sikkim Gangtok spent a second night out in the open on Monday night. Many took refuge in the city\'s football stadium, slinging plastic sheets over the goalposts or sleeping on the terraces. There was some relief as power, cut off by the quake, was restored, but landlines and mobile communications were erratic.Meanwhile, convoys of vehicles carrying rescue workers, medical teams and emergency supplies to the worst-affected districts of Mangan and Sangthan, some 60 kilometers away, left Gangtok Tuesday morning. Progress was slow because of the narrow and badly-damaged roads. The army said it could take up to 48 hours to clear the entire stretch of road to the quake epicenter.More than 5,000 army troops have been mobilized across the remote state to assist with the relief operation. By Tuesday morning, 26 tourists, including 15 trekkers, had been rescued and taken to army encampments for their own safety. Air force officials said food packages and small medical teams with doctors and paramedics had been air-dropped into isolated areas. Helicopters that had been grounded most of Monday by heavy rains and low-lying clouds were operational thanks to a break in the monsoon weather.The death toll from building collapses and landslides in Sikkim stood at 50 on Tuesday, but Indian Home Secretary R.K. Singh warned the number could rise as emergency relief workers reached far-flung villages. \"We cannot rule out more casualties,\" he told a news briefing in New Delhi.In Nepal, eight people were killed and hundreds of homes destroyed or damaged in the east of the country, where rescuers faced the same problems as their Indian counterparts with rains and mudslides blocking the only highway. Seventeen other people died in the Indian states of Bihar and West Bengal, while China\'s official Xinhua news agency said seven people had been killed in southern Tibet, near the border with Sikkim.