Xi'an is at the epicentre of China's current Covid outbreak, and authorities have enacted drastic measures.
All 13 million residents are confined to their homes and cannot leave to buy food or supplies.
Authorities are hoping to eliminate the outbreak before Lunar New Year and the Winter Olympics in Beijing next month.
The situation in Xi'an has led to heightened tensions, with many taking to social media in recent days to complain.
Authorities have been providing free food to households, but some have said their supplies are running low or that they had yet to receive aid.
In the latest incident, residents in the Mingde 8 Yingli housing compound in the south of Xi'an were reportedly told just after midnight on 1 January that they had to leave their homes and go to quarantine facilities.
It is thought this was due to recent reported infections in the community. Multiple Chinese outlets reported that locals had mixed while getting tested for Covid.
It is not known exactly how many people were transferred, but one person on social media reported seeing 30 buses outside the compound, while another claimed up to a thousand people were moved.
A number of people said they had been left waiting on the buses for several hours. Those taken to the quarantine facilities included elderly people, young children and pregnant women, according to reports. A picture of an old man standing alone in the cold wintry night as he waited to be transferred went viral, sparking pity online.
Some people posted images of the isolation facilities claiming the amenities were too basic, it was too cold, and that they had not been given food.
"There is nothing here, just basic necessities... Nobody has come to check up on us, what kind of quarantine is this? They did a big transfer of us, more than a thousand people, in the night and many of us are elderly people and children. They didn't make any proper arrangements and so they just carelessly placed us [here]," read one comment posted by an affected resident.
It has sparked widespread concern on social media platform Weibo, with many questioning the necessity of the move as residents had been quarantining in their homes for around two weeks.
They were initially given some freedom to buy food, but last week Xi'an authorities tightened the rules further and mandated that residents could leave their homes only to get tested for Covid.