SHANGHAI -Shanghais Covid-19 cases jumped to a three-month high and the stealth rollout of restrictions spread to other major cities across the country as officials try to contain the virus just days before one of Chinas most important political events.

The financial hub reported 47 new infections for Wednesday, the most since July 13 when a brief rise in cases revived fears of another general lockdown. Of the latest cases, all but two were found in quarantine. Beijing recorded 18 cases. Nationwide, there were 1,406 new local cases, down from 1,709 the day before.

While small by international standards, the flare-up is occurring just days before Chinas once-in-five-years Party Congress, when President Xi Jinping is expected to secure a precedent-breaking third term in power. So far, Chinas most important cities have avoided large-scale shutdowns, with officials instead quietly halting a growing list of activities.

Several schools in Shanghai have suspended in-person classes as the fear of infection spread grows, according to parents and social media posts. The port city of Tianjin has locked down one district and the southern megacity of Guangzhou has shut schools in one area. Zhengzhou, an iPhone manufacturing hub, has quietly locked down at least two districts. The steel city of Anshan told all of its residents to stay at home.

China is reinforcing its commitment to Covid Zero, which Mr Xi has made a cornerstone of his leadership and is likely to trumpet at the Party Congress, despite its heavy social and economic toll. The countrys propaganda machine has ramped up its defence of the controversial policy this week, with one of its top virus officials joining the chorus on Thursday, in a sign there will be no shift towards living with the virus any time soon.

Shanghais flare-up has left many of the citys 25 million on edge as the creeping restrictions stoke concerns about a broader lockdown. As well as the ad hoc school closures, at least five districts have closed entertainment venues, including cinemas, bars and gyms, in an effort to stamp out transmission, according to statements issued by Covid-19 prevention offices.

Authorities in the financial hub said on Sunday there is no citywide school shutdown after speculation rippled through social media that the measure would be rolled out. Some neighbourhoods are locked down, while individual compounds in other areas have been barricaded with the green fences that were a feature of the extended shutdown earlier this year.

So far, lockdown nerves and the risk of getting caught in Chinas policy of isolating both Covid-19 cases and close contacts have only seen a small decline in subway ridership. Daily trips have retreated from their pre-Golden Week level, but are roughly in line with Augusts ridership, according to data compiled by Bloomberg. More On This Topic Shanghai shuts down schools, gyms, bars as Covid-19 returns Lockdown worries return to Shanghai as China Covid-19 tally climbs In Tianjin, which reported just one infection for Wednesday, the Nankai district has been shut down, with people not able to leave their residential compounds and non-essential businesses closed. Guangzhous Huadu area shut entertainment venues as well as schools, and residents are undergoing mass testing. The city posted 13 new cases.

In Henan province, large parts of two districts in Zhengzhou appear to have been locked down, according to social media posts and residents who have received notification from neighbourhood committees. It has taken many people by surprise after authorities on Tuesday said there would not be a citywide lockdown.

The city reported 18 new cases for Wednesday. The Covid taskforce line for Zhengzhou city, as well as Gaoxin and Zhongyuan districts, were engaged and calls by Bloomberg News were not answered.

Residents took to social media to complain about the stealth shutdown. They echo sentiments from Shanghai residents, who have lamented the never-ending cycle of shutdowns and reopenings that is a feature of Covid Zero, and speculated whether they may face another lockdown just months after a two-month ordeal that saw many in struggle to access food and medical care.

Elsewhere, about two dozen police patrolled a busy Beijing intersection after photos and videos circulated of a rare protest attacking Mr Xi and the Covid Zero policy. One banner unfurled on a bridge in the capital said we want food, not PCR tests. We want freedom, not lockdowns and controls, along with other slogans.BLOOMBERG More On This Topic China reports fewer Covid-19 cases overall but Shanghai numbers rise Shanghai's two-month Covid-19 lockdown is still rippling through economy Related Stories What you need to know about S'pore's new Covid-19 vaccination strategy Asia stepping up fight against more infectious Covid-19 variants Hong Kong cements Covid-19 tests with centres just a 15-minute walk Covid-19 wave looms in Europe amid vaccine fatigue and false sense of security Long Covid remains a mystery, though theories are emerging askST: What is excess death and what is Covid-19's true toll on the world? Biden says pandemic is over; survivors and doctors disagree No plans to include Covid-19 vaccinations in childhood immunisation schedule: Ong Ye Kung Human development set back 5 years by Covid-19, other crises: UN report Covid-19's harmful effects on the brain reverberate years later: Study