Earthquakes measuring 6.8 on the Richter Scale shook China's west including Tibet and the Xinjiang Uygur Autonomous Region, the National Seismological Network reports.
At least 30 people have been killed in an earthquake and several aftershocks that struck Lhasa, the Tibetan capital, and surrounding areas, Chinese state media reports.
A second earthquake hit the mountainous area near Wuqia,
a town of 42,000 people in the Kizilsu Kirgiz Autonomous Prefecture, in Xinjiang Uygur Autonomous Region.
The source of the earthquake was 33 kilometres below ground. No casualties were reported so far.
Four aftershocks were detected, with magnitudes ranging from 3 to 5.7.
Xinhua reports that residents in Kashi, a city near the epicentre, felt the earthquake.
In neighbouring Kyrgyzstan, 70 people died and 120 buildings were destroyed.