More than 400 people trapped by rubble in earthquake-stricken Tibet have been rescued, Chinese officials said on Wednesday, with an unknown number still unaccounted for in freezing weather a day after a strong tremor rocked the Himalayan foothills. The epicentre of Tuesday’s magnitude 6.8 quake, one of the region’s most powerful tremors in recent years, was located in Tingri in China’s Tibet, about 80 km (50 miles) north of Mount Everest, the world’s highest mountain. It also shook buildings in neighbouring Nepal, Bhutan and India. Twenty-four hours after the temblor struck, those trapped under rubble would have endured a night in sub-zero temperatures, adding to the pressure on rescuers looking for survivors in an area roughly the size of Cambodia. Temperatures in the high-altitude region dropped as low as minus 18 degrees Celsius (0 degrees Fahrenheit) overnight. People trapped or those without shelter are at risk of rapid hypothermia and may only be able to live for five to 10 hours even if uninjured, experts say. Footage broadcast on state television CCTV showed families huddled in rows of blue and green tents quickly erected by soldiers and aid workers in settlements surrounding the epicentre, where hundreds of aftershocks have been recorded. At least 126 people were known to have been killed and 188 injured on the Tibetan side, state broadcaster CCTV reported. No deaths have been reported in Nepal or elsewhere. The quake was so strong part of the terrain around the epicentre slipped as much as 1.6 metres (5 feet 3 inches) over a distance of 80 km (50 miles), according to an analysis by the United States Geological Survey.