Rescue workers in China ’s mountainous Tibet region are racing to reach survivors trapped under the rubble as night temperatures drop far below freezing point following a powerful earthquake.

Authorities moved more than 45,000 people in earthquake-hit Tibet to shelters in a massive rescue operation at the foot of the Himalayas as they wound down the search in a high-altitude environment where the odds of survival were always slim.

More than 400 people trapped by rubble in earthquake-stricken Tibet have been rescued, Chinese officials said, with an unknown number still unaccounted for in freezing weather a day after a strong tremor rocked the Himalayan foothills.