BEIJING: An earthquake with a magnitude of 7.3 jolted China's northwestern Qinghai province early Saturday, the US Geological Survey said - following another tremor in the country's southwest that left at least two dead.

The epicentre of the quake in Qinghai, which struck at 2:04 am (1804 GMT Friday) at a relatively shallow depth of 10 kilometres (six miles), was located about 400 kilometres southwest of the city of Xining, US seismologists said.

The quake was initially measured at a magnitude of 7.4 but then slightly revised downwards by the USGS.