A dozen people were still missing on Thursday after a 6.2-magnitude earthquake struck northwestern Gansu province late Monday and netizens questioned the speed at which rescue operations ended.

Chinese media reported that search and rescue work in Gansu ended at 3 p.m. (0700 GMT) on Tuesday, about 15 hours after the disaster hit a remote and mountainous area near the border straddling Gansu and Qinghai provinces. It was not immediately clear whether the search in Qinghai was continuing.

In Gansu, 113 people had been found dead as of 9 a.m. on Wednesday (0100 GMT) and 782 were injured, authorities said. Gansu has not reported any missing person.

Neighbouring Qinghai saw its death toll rose to 22 with 198 injured and 12 missing as of 8:56 p.m. on Wednesday.

More than 207,000 homes were wrecked and nearly 15,000 collapsed in Gansu, affecting more than 145,000 people.

Discussions online showed netizens curious about how quickly rescue efforts wrapped up in Gansu, with many suggesting that the sub-freezing temperatures were the main factor in shortening the "golden period" for finding survivors - typically 72 hours post-disaster.

People trapped under rubble exposed to prolonged temperatures of -10° Celsius (14°F) run the risk of rapid hypothermia and may only be able to live for five to 10 hours even if uninjured, local media reported, citing researchers.

"They would have been dead by the time they were found, even 24 hours is already too long. Outdoor temperatures are below minus 10 C," a user on Chinese microblogging platform Weibo commented.

Some users on Weibo considered other factors such as that the search area was not especially wide, and that people have been all accounted for, leading to rescue efforts ending in less than a day.

Many of the affected families are Hui people, an ethnic minority mostly found in western Chinese provinces and regions such as Gansu, Ningxia and Shaanxi.

Rescuers on Wednesday pulled to safety several victims of the earthquake, which jolted Jishishan county in Gansu a minute before midnight on Monday, sending many residents in the area out of homes into the cold in the dead of the night.

Survivors face uncertainty in the wintry months ahead without permanent shelter amid freezing temperatures.

Roads, power and water lines and agricultural production facilities have suffered damage, and the quake triggered land and mudslides that swept through villages in Qinghai's Haidong where the missing were reported from.