There was some disagreement over the size and power of the earthquake.
The US Geological Survey reported a magnitude-6.5 quake 35 kilometers (22 miles) west-southwest of Yongle, Xinhua reported it was 7.0-magnitude, citing the China Earthquake Networks Center.
Residents in Chengdu, the provincial capital - 300 kilometers (186 miles) away from the epicenter -- told state media they had felt the quake.
Almost 400 fire trucks and more than 1,100 firefighters were dispatched to the scene, CCTV said. They are bringing with them 55 life detectors, 30 rescue dogs and 24 generators.
Local authorities announced the closure of the Jiuzhaigou tourist area, which includes a national park known for its waterfalls and topographical formations, beginning Wednesday.
Yu Qian, a local taxation bureau official, told Xinhua that the earthquake cut off power and disrupted phone service in her neighborhood.
The quake struck at 7:27 a.m. local time. Its epicenter was 107 kilometers (67 miles) south-southeast of Dostq, Kazakhstan, at a depth of 25.9 kilometers (16 miles), the USGS said.
There were no immediate reports of casualties or damage, due to the sparsely populated nature of the area.