BEIJING, Sept 5 (Reuters) - An earthquake of magnitude 6.8 struck a mountainous area in the west of China's Sichuan province after midday on Monday, the China Earthquake Networks Centre said.

The epicentre was located at the town of Luding at a depth of 16 kilometers, the centre said, about 180 km (111 miles) southwest of Sichuan's capital Chengdu.

Netizens from as far away as Changsha and Xian said they had felt the quake in Sichuan.

Minutes later, a second quake with a magnitude of 4.2 struck the city of Yaan near Luding, according to the centre.

No casualties have been reported so far.

In 2013, Yaan was hit by a strong earthquake, killing more than 100 people and injuring thousands.