Thousands of rescue workers in north-west China are digging through rubble to reach survivors of a major earthquake which killed more than 260 people. At least 4,000 people were injured in Monday's quake which rocked two counties in the Xinjiang region. In the worst-hit county of Bachu, entire villages have been wiped out by the tremor, measured at 6.8 on the Richter scale, local officials said. "There are 249 dead in one of the villages and 12 dead in other villages," Xinjiang Earthquake Bureau official Zhang Yong told the AFP news agency.