Firefighters are on the scene to provide relief, and the air wing of the Western Theatre Command flew an emergency command group to the disaster area on Tuesday morning to handle the armed forces’ rescue operations.

Gansu province’s traffic police said it was controlling traffic in the quake-hit area and asking motorists to avoid it if not involved in rescue efforts.

Gansu authorities also said roads and rail lines damaged in the quake were back in service by Tuesday morning, but some trains were delayed.

The Ministry of Water Resources said efforts were under way to repair water supply lines in quake-hit rural areas.

The quake struck at 11.59pm on Monday, with the epicentre in a township in Jishishan, an autonomous county with a population of 280,000 and some 102km (63 miles) from the provincial capital Lanzhou. Several regions in western and central China reported tremors.

Cold snap freezes China, bringing snow, accidents and school closures

By Tuesday morning, nine aftershocks of magnitude 3 or higher had been recorded, Gansu authorities said.

Aftershocks of magnitude 5 or higher were possible in the coming days. Electricity in Jishishan county was disrupted and restored around 9am on Tuesday.

The Ministry of Transport, which monitors the operation of roads, said on Tuesday morning that a bridge across the Yellow River had cracked because of the quake.

Residents interviewed by Shanghai-based media outlet The Paper said many people were asleep when the quake struck and did not have time to take shelter. The Paper also quoted a woman 90km from the epicentre who said her house collapsed and she escaped being buried because she was still awake.

Mainland media reported there was a lack of heating equipment in the quake-hit areas. Beijing-based magazine China Newsweek quoted a disaster rescuer saying the low temperatures could make rescues more difficult.

Videos and photos circulating on social media showed firefighting crews trying to pull out residents buried under rubble and others showed quake victims taking shelter on the road while wrapped in quilts.

State broadcaster CCTV reported that silt had washed into a village in Qinghai province near Gansu after the earthquake, stranding residents. Thirteen people from the village were missing.

The National Health Commission has sent medical experts from top hospitals to the disaster area to provide support, according to CCTV.

Gansu province’s top two officials – provincial Communist Party secretary Hu Changsheng and governor Ren Zhenhe – also headed to the disaster area early on Tuesday.

Both a State Council office in charge of disaster relief and the Ministry of Emergency Management, responsible for disaster response, sent working groups to the affected areas.

The Ministry of Emergency Management and the Ministry of Finance jointly released 200 million yuan (US$28 million) in relief funds for Gansu and Qinghai.

The China Earthquake Networks Centre said preliminary analysis showed that the quake was a thrust-type rupture.

It said the epicentre was on the northeastern edge of the Tibetan Plateau and in a seismic zone. The quake was the latest of three earthquakes of magnitude 6 or higher that have struck within 200km of the epicentre since 1900.

The Hong Kong government said it had not received any request for help from city residents in Gansu. It would discuss with mainland authorities whether to send rescue teams to aid the mission.

“We will pay close attention to the situation and contact local rescue organisations to apply for our Disaster Relief Fund to provide appropriate assistance to our compatriots in need. As it is winter time, it is very cold in Gansu so rescue efforts cannot be delayed,” acting chief executive Eric Chan Kwok-ki said.

Chief Executive John Lee Ka-chiu offered his condolences to the families of those killed.

“And [I] wish the injured a speedy recovery,” he said on his Weibo account.

Lee added that he had instructed the Hong Kong government to liaise with disaster relief organisations and “provide appropriate support” through the Disaster Relief Fund.

Taiwanese President Tsai Ing-wen also offered her condolences, adding that Taiwan “stands ready to offer assistance in the disaster response effort”.

Similar sentiments came from several embassies in Beijing, including the embassies of the United States, Canada, Japan, France, Iran and Israel.

In a message to Xi, Russian President Vladimir Putin said: “In Russia, they share the grief of those who lost their loved ones as a result of this disaster, and hope for a speedy recovery of all victims.”

Additional reporting by Lo Hoi-ying