Bachu county, the worst-hit area in the far western region of Xinjiang, was hit by 1,924 aftershocks from Monday morning to Thursday afternoon, a county official told Deutsche Presse-Agentur dpa by telephone.
The China Seismological Bureau has warned that the area could face aftershocks of up to 6.0 on the Richter scale this week.
But state media said the frequency of aftershocks had diminished from 40 per hour on Monday to about 20 per hour on Thursday.
Some 270 people died in Bachu, nearly all of them in the country's Qongkurqak township, officials said.
Sub-zero nighttime temperatures had dropped on Wednesday, but enough tents had arrived to accommodate all homeless people in Bachu, they said.
About 20,000 local people, aided by rescue workers and soldiers, were continuing relief operations on Thursday.
Monday's earthquake measured 6.8 on the Richter scale. About 4,000 people were injured, 2,500 of them seriously. Some 50-60 per cent of the injured were elderly people trapped in collapsed adobe houses, officials said.
Doctors said they were ''overwhelmed'' at five hospitals treating some 600 of the most seriously injured people in Bachu county.
Most of the injured suffered head and limb injuries from falling debris. The poor quality of many timber-framed adobe houses had contributed to the high number of casualties, officials said. dpa bs rk
- Deutsche Presse Agentur
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