BEIJING (Reuters) -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.