The drastic measures are linked.
Beijing closed dozens of metro stations on Wednesday to fight against Covid-19, restricting the movement of residents even if the Chinese capital of 21 million inhabitants has only a few dozen daily cases.
Largely spared for two years, China has faced its worst epidemic outbreak in recent weeks since the spring of 2020, which has undermined its zero Covid strategy.
Residents of Beijing, where 51 new cases were reported on Wednesday, fear their city will be locked down, like Shanghai, China's largest city with 25 million people, where most cases are recorded.
Sixty stations closed
The Beijing Metro announced the closure of about 60 stations on Wednesday, or about 18% of the network, many of which are near confined areas, according to its WeChat page.
“The entrances and exits of the stations will be closed… But the changes (of line) can be made inside the stations”, specifies the opinion.
The metropolis of Shanghai, the country's economic capital, where residents have been confined for more than a month, recorded nearly 5,000 new cases on Wednesday, a figure down as the city eased certain measures.
Anyone who tests positive is sent there to a quarantine center, with variable comfort and often deplorable hygienic conditions.
Padlocked residences
In Beijing, residential complexes where contamination has been identified are padlocked to prevent residents from leaving.
Municipal government spokesman Xu Hejian told reporters on Wednesday that the capital would "temporarily extend" restrictions, including banning restaurants and closing entertainment venues and sports clubs.
Officials initially said the restrictions would end with the end of the Labor Day holiday on Thursday.
During these holidays, during which the Chinese usually travel in a massive way, the tourist sites were almost deserted.
To curb contagion, restaurants are prohibited from welcoming customers and can only sell take-out.
Residents have started stocking up on food and basic necessities for fear of lockdown.
"The city already half confined"
But authorities also appeared to be relaxing some rules, with Xu Hejian saying people arriving in Beijing from overseas would be required to observe a 10-day supervised quarantine and one week of home isolation, down from 21 days of quarantine previously.
“I think the city is already half-locked down,” said a Beijing resident, whose residential complex is cordoned off by authorities, on condition of anonymity.
"There is no timetable for a lifting of this measure and more and more places are sealed off," he told AFP.
Another resident, 35, said he shopped online to avoid contact with people in supermarkets.
“Nobody can really say how long the restrictions will last… But I understand the reasoning,” he said.
On Tuesday, all residents of Chaoyang District, the capital's most populous district, began a new round of screening tests which are due to end on Thursday.
Elsewhere in China, the city of Zhengzhou in the center of the country has also stepped up anti-Covid checks as residents of the city center have been ordered to stay in their housing compounds.