Urumqi -- A 6.8 magnitude earthquake shook northwest China on Sunday night, said the National Seismological Network.

So far, no casualties have been reported, XINHUA news agency reported Monday.

The epicenter was fixed at 39.6 degrees north latitude and 73.9 degrees east longitude, in a mountainous area about 100 km away from the county seat of Wuqia, Kizilsu Kirgiz Autonomous Prefecture. The source of the earthquake was 33 kilometers underground.

Xinjiang earthquake monitoring network Monday said it observed four after shocks with magnitudes ranging from 3 to 5.7 after the quake hit Sunday at 23:52 p.m.

In Simuhana, the nearest village to the quake's epicenter, some houses had cracks and broken windows but mobile telecom signal was still available.

Villagers said they felt the quake when it struck. Everybody in the village was unharmed.

A Xinhua reporter said residents in Kashi, another city near the epicenter, also felt the strong earthquake.

Wuqia County is located in the Pamirs, in the southwestern part of Xinjiang at the conjunction of the southern side of the Tianshan Mountains and the Kunlun Mountains.

With a population of 42,002, Wuqia, 1,500 kilometers away from Urumqi, the regional capital of Xinjiang, is quake prone. Since 1889, there have been seven powerful quakes measuring more than seven on the Richter scale.

The county was hit by a 3.8 magnitude earthquake on September 22 this year.