Updated at 11:55 p.m. BJT
Five people have been confirmed dead and 63 others injured, according to the local emergency office.
The deceased are all tourists.
Earlier, Sichuan local television said at least four people were killed and more than 30 others injured in the earthquake.
A total of 106 aftershocks were recorded as of 11 p.m. BJT, according to the China Earthquake Networks Center (CENC).
A total of 610 fire officers and soldiers, and eight sniffer dogs were dispatched to the scene after the earthquake.
Updated at 10: 44 p.m. BJT
Tibetan and Qiang Autonomous Prefecture of Aba has activated a level-I emergency response, the highest of a four-tier system, following the earthquake.
The Health and Family Planning Commission of Sichuan Province has launched an emergency response and has sent rescue groups to the area.
A resident in a village near Jiuzhaigou told CGTN that no buildings had collapsed. But a strong shaking was felt.
People fled outdoors after the earthquake./ Weibo Photo
According to local media Sichuan Online, 14 trains passing Jiuzhaigou were suspended over safety concerns.
The epicenter is close to Jiuzhaigou Valley, a World Heritage site which is famous for its colorful pools and snowy mountains.
Sichuan suffered a magnitude-8 earthquake in 2008 and a magnitude-7 quake in 2013.
Updated at 10 p.m. BJT
An aftershock with a magnitude of 3.3 shook Jiuzhaigou County of southwest China's Sichuan Province at 9:41 p.m BJT at a depth of nine kilometers after the initial quake, according to the China Earthquake Networks Center (CENC).
The epicenter of the initial magnitude-7.0 earthquake was 39 kilometers from Jiuzhaigou, 285 kilometers from Chengdu, Sichuan's provincial capital.
Tremor were felt in Chengdu as well as in the neighboring Gansu and Shaanxi provinces.
Updated at 9:41 p.m. BJT
A magnitude-7.0 earthquake jolted Jiuzhaigou County in southwest China's Sichuan Province at 9:19 p.m. BJT on Tuesday, according to the China Earthquake Networks Center (CENC).
The earthquake struck at a depth of 20 kilometers. The epicenter was monitored to be at 33.20 degrees north latitude and 103.82 degrees east longitude.
There were no immediate reports of casualties and property damages are yet to be calculated.