A magnitude-6.2 earthquake jolted a remote and mountainous county on the northern edge of the Qinghai-Tibetan plateau just before midnight on Monday, killing at least 118 people and injuring hundreds, according to Chinese state media.
Authorities have mobilised an array of emergency responses, but rescue work could prove challenging in subzero temperatures. Most of China is grappling with freezing temperatures as a cold wave that started last week continued to sweep through the country.
Twenty people have been reported missing in the quake's aftermath after hours of rescue and relief efforts that began before sunrise, according to state media.
Earthquakes are common in western provinces such as Gansu, which lie on the eastern boundary of the Qinghai-Tibetan plateau, a tectonically active area.
The epicentre of the latest quake was 5 km from the border between Gansu and a neighbouring province. Strong tremors were felt in many parts of Qinghai province, the official Xinhua news agency said.
The quake struck Jishishan county in China's northwestern province of Gansu at 11:59 pm local time (1559 GMT) on Monday at a depth of 10 km, according to China Earthquake Networks Center (CENC).
In Gansu, 105 were killed in the quake as of 7:50 am Tuesday (2350 GMT Monday), and of 397 injured as of 9:30 am, 16 were in critical condition, provincial authorities told a news conference.
The death tally in Qinghai rose to at least 13 with 182 injured, state media reported.
About 2,200 rescue personnel from the provincial fire department and 900 from the forest brigade, as well as 260 professional emergency rescue personnel, were dispatched to the disaster zone, Xinhua reported, adding that the military and police were also engaged in rescue work.
China's Ministry of Emergency Management upgraded its earthquake emergency response to second-highest level, Xinhua reported. Its national health commission sent a team of medical experts and coordinated emergency teams from other provinces.
The province, which has allocated 20 million yuan ($2.8 million) to the local government for emergency response work, also sent supplies that included 2,600 cotton tents, 10,400 folding beds, 10,400 quilts, 10,400 cotton mattresses, and 1,000 sets of stoves.
Local authorities have also imposed traffic restrictions into Jishishan for until rescue work is done, CCTV said. Social volunteers are requested not to enter the disaster zone as well, local media said.