A strong earthquake with a magnitude of 6.6 struck China's remote northwestern Qinghai province early Saturday, the US Geological Survey said.
The epicentre of the quake, which struck at about 1:45 am (1745 GMT) at a shallow depth of 10 kilometres (six miles), was located about 140 kilometres north-northwest of the city of Xining, US seismologists said.
A 5.1-magnitude aftershock followed about 25 minutes later, USGS said.
The sparsely populated province is spread across the Tibetan plateau.
In 2010, a 6.9-magnitude quake in Qinghai left 3,000 people dead or missing.
