Millions of people in Beijing are being tested for COVID-19 after the Chinese capital recorded three new cases on Friday.
Provinces around the country have also been ordered to prepare mass quarantine facilities.
Mainland China has a current total of 1,960 officially confirmed cases, but the government is going to extraordinary lengths to stop limited outbreaks turning into a second wave.
China has been recording more than 100 cases each day for more than a week – a low number compared with Western countries but its highest rate since March. Another 103 cases were recorded on Friday.
Nearly exactly a year since the first lockdown in Wuhan, unprecedented at the time, tens of millions of people are once again living under similar restrictions.
Lockdown rules are much stricter than in countries with much higher rates of COVID.
Residents in some areas of Shijiazhuang, the capital of Hebei province which borders Beijing, are not allowed to leave their houses at all.
Others in lower risk areas are allowed to go outdoors but must stay within their residential compounds, and shops and restaurants are shut.
A video posted on Chinese social media showed a man being restrained and tied to a tree by epidemic control workers after he went outside for a walk.
The workers shouted at the man: “You’re outside when the pandemic situation is so serious! How dare you! Tie him up tightly! F*** you!”
The village official in charge of the workers was suspended and is being investigated, authorities said.
Despite the severity of the restrictions, many Chinese people are supportive of the measures.
One Shijiazhuang resident, who has been tested for COVID-19 three times over recent days, told Sky News: “I think the strict policy is very necessary and is carried out in time. Thanks to the strict policy, the pandemic should be controlled.
“We are never worried – because we believe in government’s control.”
Chinese officials laid the blame for the new cases at infections imported from abroad.
Earlier in the week, they confirmed that the B.117 COVID variant first identified in the UK had been found in China.
Feng Zijian, deputy director of the Chinese Centre for Disease and Control and Prevention, said: “The epidemiological investigations show that these outbreaks were not related to previous infections, but caused by newly imported sources of the virus.
“According to source-tracing investigation, the cluster infections reported in China since the winter are all caused by imported cases, inbound visitors and imported goods, which mainly occurred in cities with airports, land ports and sea ports where there are people and good flowing in.”
China has boasted, very publicly, of its success in controlling the coronavirus – and credited those achievements to the leadership of the Chinese Communist Party.
Quite simply, things cannot be allowed to get out of control.