The country's leadership faced a weekend of protests not seen in decades as anger over unrelenting lockdowns fuels deep-rooted frustration with its political system.
A deadly fire last week in Urumqi, the capital of the northwestern region of Xinjiang, was the catalyst for the wave of outrage, with protesters taking to the streets in cities around China.
The demonstrators said Covid-19 restrictions were to blame for hampering rescue efforts, claims the government has denied as it accused "forces with ulterior motives" of linking the fire deaths to the strict Covid controls.
Anger over lockdowns has widened to calls for political change, with protesters holding up blank sheets of paper to symbolise the censorship to which the world's most populous country is subjected.
- 'So many police' -
More protests had been planned for Monday night but did not materialise. AFP journalists in Beijing and Shanghai noted a heavy police presence of hundreds of vehicles and officers on the streets.
People who had attended weekend rallies told AFP on Monday they had received phone calls from law enforcement officers demanding information about their movements.
In Shanghai, near a site where weekend protests saw bold calls for the resignation of President Xi Jinping, bar staff told AFP they had been ordered to close at 10:00 pm (1400 GMT) for "disease control".
Small clusters of officers were deployed to metro exits near the protest site.
AFP journalists saw officers detaining four people throughout Monday, releasing one later, with a reporter counting 12 police cars within 100 metres along Wulumuqi street in Shanghai, the focal point of Sunday's rally.
Frustration with zero-Covid remained palpable despite the overwhelming police deployment.
"The (zero-Covid) policies now -- they're just too strict. They kill more people than Covid," one 17-year-old passerby, who asked to be identified only as Ray, told AFP.
He said he had been surrounded by police when passing through the area.
A man can be heard in an audio recording shared with AFP asking for his address. In response, Ray insists law enforcement officers do not "have the right" to demand it.
Some rallies did go ahead elsewhere on Monday night.
In semi-autonomous Hong Kong, where mass democracy protests erupted in 2019, dozens gathered at the Chinese University to mourn the victims of the Urumqi fire.
"Don't look away. Don't forget," protesters shouted.
In Hangzhou, just over 170 kilometres (105 miles) southwest of Shanghai, there was strict security and sporadic protests in the city's downtown, with one attendee telling AFP that 10 people were detained.
"The atmosphere was disorderly. There were few people and we were separated. There were lots of police, it was chaos," she said.
- 'Many died in vain' -
Such widespread rallies are exceptionally rare, with authorities harshly clamping down on all opposition to the central government.
But China's strict control of information and continued travel curbs have made verifying protester numbers across the vast country challenging.
US President Joe Biden is monitoring the unrest, the White House said Monday.
Solidarity protests also mushroomed around the world.
"Officials are borrowing the pretext of Covid, but using excessively strict lockdowns to control China's population," one 21-year-old Chinese participant in a Washington protest, who gave only his surname, Chen, told AFP.
"They disregarded human lives and caused many to die in vain," he said.
- 'No longer afraid' -
China's leaders are committed to zero-Covid, which compels local governments to impose snap lockdowns and quarantine orders, and limit freedom of movement in response to minor outbreaks.
But there are signs that some local authorities are taking steps to relax some of the rules and dampen the unrest -- and that authorities may be seeking a path out of the rigid policy.
Beijing has banned "the practice of barring building gates in closed-off residential compounds", the official news agency Xinhua said on Sunday.
The practice has fuelled public anger as people found themselves locked in their homes during minor outbreaks.
China's National Health Commission announced on Tuesday a renewed effort to expand low vaccination rates among the elderly -- long seen as a key obstacle to relaxing zero-Covid.
Many fear that lifting the policy while swaths of the population remain not fully immunised could overwhelm China's healthcare system and cause more than a million deaths.
Just 65.8 percent of people over 80 are fully vaccinated, NHC officials told a news conference.
China has also not yet approved mRNA vaccines, which are proven to be more effective, for public use.
They also said local efforts "inconsistent with national policies" had caused a "great impact on people's work and life", but did not suggest a change in policy was imminent.