Protests have simmered in Shanghai as residents in several Chinese cities, many of them angered by a deadly fire in the country’s far west, push back against heavy COVID-19 curbs almost three years into the pandemic.

A fire on Thursday that killed 10 people in a high-rise building in Urumqi, capital of the Xinjiang region, has sparked widespread public anger as many internet users surmised residents could not escape in time because the building was partially locked down – a claim city officials denied.

In Shanghai, China’s most populous city and financial hub, residents gathered on Saturday night at Wulumuqi Road – which borrows its name from Urumqi – for a vigil that turned into a protest in the early hours of Sunday.

“Lift lockdown for Urumqi, lift lockdown for Xinjiang, lift lockdown for all of China!” crowds shouted, according to a video circulated on social media.

At one point a large group began shouting, “Down with the Chinese Communist Party, down with Xi Jinping, free Urumqi!”, according to witnesses and videos, in a rare public protest against the Chinese leadership.

A large group of police looked on and sometimes tried to break up the crowd.

China is battling a surge in infections that has prompted lockdowns and other restrictions in cities across the country as Beijing adheres to a zero-COVID policy even as much of the world tries to coexist with the virus.

China defends the zero-COVID policy as life-saving and necessary to prevent overwhelming the healthcare system.

Officials have vowed to continue with it despite the growing public pushback and its mounting toll on the world’s second-biggest economy.

Videos from Shanghai widely shared on Chinese social media showed crowds facing dozens of police and calling out chants including “serve the people”, “we don’t want health codes” and “we want freedom”.

Some social media users posted screenshots of street signs for Wulumuqi Road, both to evade censors and show support for protesters in Shanghai.

Others shared comments or posts calling for all of “you brave young people” to be careful.

Many included advice on what to do if police came or started arresting people during a protest or vigil.

Shanghai’s 25 million people were put under lockdown for two months earlier this year, an ordeal that provoked anger and protest.

Chinese authorities have since sought to be more targeted in their COVID curbs, but that effort has been challenged by a surge in infections as China faces its first winter with the highly transmissible Omicron variant.

While low by global standards, China’s case numbers have hit record highs for days, with almost 40,000 new infections reported by health authorities on Sunday for the previous day.

Some residents under lockdown in Beijing staged small protests or confronted local officials on Saturday over movement restrictions, with some successfully pressuring them into lifting the curbs ahead of schedule.

A video shared with Reuters showed Beijing residents in an unidentifiable part of the capital marching around an open-air car park on Saturday, shouting “end the lockdown”.

The Beijing government did not immediately respond to a request for comment on Saturday.