An earthquake measuring 6.5 in magnitude struck a remote and mountainous part of the southwestern province of Sichuan on Tuesday, the US Geological Survey said, killing 13 people and trapping 100 tourists in a popular scenic spot.

The quake hit a sparsely populated area 200 km (120 miles) west-northwest of the city of Guangyuan at a depth of 10 km (6 miles), the USGS said. It had earlier put the quake at magnitude 6.6 and 32 km deep.

The Sichuan earthquake administration said the epicentre of the tremor was in Ngawa prefecture, largely populated by ethnic Tibetans, many of whom are nomadic herders. It was also close to the Jiuzhaigou nature reserve, a popular tourist destination.