The second phase of the closure, due to the emerging corona virus (Covid-19) in the Chinese city of Shanghai, has entered into force on an additional 16 million people living in the western part of this coastal city.
The curfew already in force in the eastern and southern provinces of the city of 26 million people was extended to the western provinces on Friday.
Until Monday, only residents will be allowed to leave their homes in order to get tested for COVID-19.
With the arrival of the mutated Omicron of the Corona virus, China experienced the worst wave of infection since the beginning of the pandemic two years ago.
Although the numbers are low compared to the numbers internationally, the government is pursuing a "zero-Covid" strategy which is being tested against the PA2 subtype of the omicron.
So far, the authorities have succeeded in combating minor outbreaks with curfews, mass checks and quarantines.
Shanghai and Jilin Province in northeastern China are currently the most affected areas.
And the Beijing Health Commission reported today that 358 new infections were recorded Thursday in the coastal city, while 4,144 other asymptomatic cases were counted.