A strong 6.3-magnitude earthquake rattled China's northwestern Xinjiang region Saturday, injuring at least 24 people according to state media.

The quake, at a shallow depth of 9.8 kilometres (six miles), had its epicentre in a remote, mountainous area 99 kilometres south of the city of Dushanzi, the US Geological Survey said.

But the tremor was felt strongly in Xinjiang's regional capital of Urumqi nearly 300 kilometres (180 miles) away, as well as in the major cities of Dushanzi and Kuitun, China Central Television said.

At least 24 people were reported injured, one of them seriously, Xinhua news agency said. Many of the victims were hurt when houses collapsed, it said, and others were tossed from their beds.

The quake struck at 5:07 am (2107 GMT Friday), while nearly 200 aftershocks had occurred in the area by noon, the biggest measuring 4.2 in magnitude, Xinhua said.

Rescue teams were immediately dispatched to populated areas hit by the quake, CCTV said.

Later Saturday, CCTV reported that 22,000 people had been affected by the quake, while over 1,600 homes had collapsed.

The south Xinjiang railway was affected, it reported, but details were not immediately clear, and electricity was cut off in some quake-hit areas.

The China Earthquake Networks Centre measured the quake at 6.6 on the Richter scale.

Xinjiang is a vast region with a population of around 20 million, of whom some nine million are Uighurs, a Turkic-speaking, mainly Muslim ethnic minority.