6.3-magnitude quake in Tibet

(CNN) - An earthquake measuring 6.3 in magnitude struck Tibet in western China on Monday, according to the U.S. Geological Survey

The strong quake hit the autonomous region at 9:22 p.m. (9:22 a.m. ET), according to the USGS. Two aftershocks, measuring 5.3 and 5.1 in magnitude, struck the same region in the hour after the initial quake.

The epicenter of the 6.3-magnitude temblor was in a mountainous region in southwestern Tibet's Shigatse Prefecture, which borders Nepal. China's state-run Xinhua news agency said the area - with an average altitude of 5,500 meters (18,045 feet) - is sparsely populated.

There were no initial reports of casualties or major damage in either Nepal or Tibet.