Two earthquakes measuring 5.7 and 5.5 magnitudes on the Richter Scale struck southwest China's Tibet Autonomous Region within an hour on Wednesday, said the China Earthquake Networks Center.

The first 5.7-magnitude quake occurred at around 10:06 a.m. and the second 5.5-magnitude one came 38 minutes later, both in northern Tibet's Nyainrong County, Nagqu Prefecture.

The epicenter of the first quake was 32.4 degrees north latitude and 93.0 degrees east longitude at a depth of about 8 kilometers.

The epicenter of the second quake was 32.5 degrees north latitude and 92.8 degrees east longitude at a depth of about 7 kilometers, according to the center.

The quake hit a sparsely inhabited mountainous area with an altitude of more than 4,000 meters, said Zhu Quan, director with the seismological bureau of Tibet.

The region suffered frequent quakes in the past years, said Zhu.

The bureau has sent a team headed by the deputy director to the site of the quake.

No reports of casualties or damage are immediately available.