At least 105 were killed and almost 400 injured in Gansu province, local officials said, after the strong, shallow tremor struck around midnight.
According to state broadcaster CCTV, 11 others were killed and 100 injured in the city of Haidong in the neighbouring province of Qinghai.
The quake brought homes crashing down and caused other significant damage, sending people running into the street for safety, state news agency Xinhua said.
“I was almost scared to death. Look at how my hands and legs are shaking,” said a woman of about 30 in a video posted to a social media account associated with the state-run People’s Daily newspaper.
“As soon as I ran out of the house, the earth on the mountain gave way, thudding on the roof,” she said as she sat swaddled in a blanket outside, cradling a baby.
Footage from CCTV showed family possessions visible among strewn masonry from a house that caved in during the quake.
Rescue work was under way early Tuesday, with Chinese President Xi Jinping calling for “all-out efforts” in the search and relief work.
Temperatures are below freezing in the high-altitude area, and rescuers should be on guard for secondary disasters, he said according to CCTV.
The quake, which was logged as magnitude 5.9 by the US Geological Survey, struck in Gansu near the border with Qinghai, where Haidong is located.
That epicentre is about 100 kilometres (60 miles) southwest of Gansu province’s capital, Lanzhou.
Xinhua reported the quake — which was felt in the major city of Xi’an in northern Shaanxi province, about 570 kilometres (350 miles) away — as being magnitude 6.2.
Several smaller aftershocks followed the initial earthquake, and officials warned that tremors with a magnitude of more than 5.0 were possible in the next few days.
A quake measured at magnitude 5.2 by USGS was detected further northwest in Xinjiang province on Monday morning.
Freezing temperatures
Power and water supplies were disrupted in some villages around the epicentre, Xinhua said.
Footage from one of the worst-hit places on CCTV showed residents warming themselves by a fire while emergency services set up tents.
CCTV said more than 1,400 firefighters and rescue personnel had been sent to the disaster zone, while another 1,600 remained “on standby”.
The broadcaster added that supplies including drinking water, blankets, stoves and instant noodles were also being sent to the affected area.
Footage showed emergency vehicles driving along snow-lined highways towards the scene with their lights flashing.
Rescue workers in overalls were pictured shoulder-to-shoulder in the trucks, while other images showed them lining up in ranks to receive instructions.
Other clips showed emergency personnel going through debris by torchlight, unfolding orange stretchers for the casualties.
Hundreds of people have been evacuated in Gansu, officials said.
The earthquake struck at a shallow depth at 11:59 pm local time Monday (1559 GMT), according to the USGS, which revised the magnitude downwards after initially reporting it to be 6.0.
Earthquakes are not uncommon in China. In August, a shallow 5.4-magnitude earthquake struck eastern China, injuring 23 people and collapsing dozens of buildings.
In September 2022, a 6.6-magnitude quake hit Sichuan province leaving almost 100 dead.
A 7.9-magnitude quake in 2008 left more than 87,000 people dead or missing, including 5,335 schoolchildren.
