MENYUAN, Qinghai, Jan. 21 -- No casualties were caused by a 6.4-magnitude earthquake that struck a county in northwest China's Qinghai province on early Thursday morning, local authorities said.

The tremor jolted Hui Autonomous County of Menyuan at 1:13 a.m.. It damaged 54 houses, including 20 with cracks in the walls, said county head Huang Jicheng.

The epicenter, 33 kilometers away from the county seat, is unpopulated, Huang said. Telecom services and traffic in the country remain normal.

Local civil affairs authorities have sent more than 700 tents to the quake-affected region. Witnesses say many scared local residents have run outdoors and some stay in cars, despite a freezing temperature of minus 20 degrees Celsius.

Dong Jinming, chief of the county committee of the Communist Party of China, said 90 percent of the county's rural houses have been renovated, which helped avoid casualties from the disaster.

A 3.4-magnitude aftershock was reported minutes after the initial quake, according to the China Earthquake Networks Center (CENC).

The CENC did not rule out the possibility of ensuing aftershocks measuring around 5 degrees on the Richter scale in the coming few days in the region, but added that more powerful tremors are highly unlikely.

"The tremor lasted one to two minutes... with a rumbling noise," said Ma Wulong, a local resident in Menyuan county.

"Everyone is out now," he told Xinhua over phone.

Li Zhanqing, deputy head of a forestry farm in Menyuan, said armed police and medical staff in the county have already been mobilized by the time he got to the downtown Menyuan.

Tremors are also felt in Xining, capital city of Qinghai Province, and in the neighboring Gansu Province.

"I was waken up from sleep by the jolt," said a man surnamed Han in Xining, "The table and the closets were all shaking violently, so I just got dressed and run outside."