A 5.7-magnitude earthquake jolted Yushu Tibet Autonomous Prefecture in northwest China's Qinghai Province at about 10:29 a.m. Saturday, according to the China Earthquake Networks.

The earthquake's epicenter was calculated at 96.3 degrees east longitude and 33.3 degrees north latitude in Longbao Town, 60 km southwest of Yushu's prefecture seat Gyegu Town. But the tremor was felt strongly in Gyegu, Xu Chuanjie, head of emergency rescue section at the provincial earthquake bureau said.

The quake focus was 10 km below the earth's surface.

According to Liu Jie, director of the quake forecast center at the China Earthquake Network, the earthquake was an aftershock of the 7.1-magnitude earthquake that hit Yushu April 14.

Liu said it was "normal for moderate or strong aftershocks to occur months after a major earthquake."

He added that more aftershocks in the region near Yushu can be expected in the near future.

Saturday's quake was followed by three more aftershocks, which measured 3.2, 3.8 and 4.1 on the Richter scale, respectively.

The three aftershocks' epicenter was almost the same - 96.2 degree east longitude and 33.3 degree north latitude.

No casualties have been reported.

From April 14 to May 28, Yushu recorded 1,873 aftershocks, of which 15 were above 3 magnitude.

The April 14 quake devastated Yushu and claimed more than 2,200 lives.