(Recasts, adds details)
BEIJING, Aug 3 (Reuters) - A magnitude 6.3 earthquake struck southwestern China on Sunday, according to the U.S. Geological Survey, which state media said was felt most strongly in a remote area of Yunnan province, adding there were no reports of casualties yet.
The quake registered at a shallow depth of less than 1 mile.
State television said on its microblog that the epicentre was in Ludian county in Yunnan province, a mountainous area that is lightly populated.
It added that communications had been seriously affected and that authorities were trying to establish if there were any casualties.
The quake was also felt in the neighbouring provinces of Guizhou and Sichuan, state media added.
China is frequently struck by quakes in this part of the country. A quake in Sichuan in 2008 killed almost 70,000 people. (Reporting by Ben Blanchard; Editing by Matt Driskill)