Authorities have abruptly lifted Covid restrictions in the Chinese cities of Guangzhou and Chongqing, where protesters scuffled with police on Tuesday night, as police searched for demonstrators in other cities and the country’s top security body called for a crackdown on “hostile forces”. After days of extraordinary protests in the country that also prompted international demonstrations in solidarity, the US and Canada urged China not to harm or intimidate protesters opposing Covid-19 lockdowns. On Wednesday afternoon, authorities suddenly announced a lifting of lockdowns in about half of the districts across the southern city of Guangzhou. Official announcements told local officials to variously remove “temporary control orders” and to redesignate areas as low risk. They also announced an end to mass PCR testing. One resident said that within an hour of the announcement they had seen apartment security staff quickly leave, and neighbours hurrying out with luggage “to escape”. The south-western city of Chongqing will allow close contacts of people with Covid-19, who fulfil certain conditions, to quarantine at home, a city official said. The easing of restrictions, which came despite rising cases in the city, did not extend to all districts. Some areas, including parts of Haizhu, where protesters scuffled with police on Tuesday night, according to witnesses and footage, remained under restrictions. The city recorded almost 7,000 Covid cases on Tuesday. In Haizhu there had been several protests and clashes with police over the past month, and it was the site of the most recent protests in a wave of civil disobedience that escalated dramatically on Friday. Late on Tuesday, security personnel in hazmat suits formed ranks shoulder-to-shoulder, taking cover under riot shields, to make their way down a street in Haizhu district as glass smashed around them, videos posted on social media showed. In the footage – geolocated by Agence France-Presse – people could be heard screaming and shouting as orange and blue barricades were pictured strewn across the ground. Others threw objects at the police and later nearly a dozen men were filmed being taken away with their hands bound by cable ties. A Guangzhou resident told AFP on Wednesday he witnessed about 100 police officers converge on Houjiao village in Haizhu district and arrest at least three men on Tuesday night. Haizhu, a district of more than 1.8 million people, has been the source of the bulk of Guangzhou’s Covid-19 cases. Much of the area has been under lockdown since late October. On Tuesday, the White House national security spokesperson John Kirby said the US stood up for peaceful protesters. “We don’t want to see protesters physically harmed, intimidated or coerced in any way. That’s what peaceful protest is all about and that’s what we have continued to stand up for whether it’s in China or Iran or elsewhere around the world,” he told CNN. Canada’s prime minister, Justin Trudeau, said on Tuesday that everyone in China should be allowed to protest and enjoy freedom of expression, and that Canadians were closely watching the protests against the country’s zero-Covid policy. “Everyone in China should be allowed to express themselves, should be allowed to share their perspectives and indeed protest,” Trudeau said. “We’re going to continue to ensure that China knows we’ll stand up for human rights, we’ll stand with people who are expressing themselves.” Discontent with China’s stringent Covid prevention strategy three years into the pandemic has ignited into protests in cities across the country, in the biggest wave of civil disobedience since the country’s leader, Xi Jinping, took power a decade ago. Chinese authorities have been seeking out people who gathered at weekend protests, some who were at the Beijing demonstrations told Reuters. The number of people who have been detained at the demonstrations and in follow-up police actions is not known. China’s foreign ministry says rights and freedoms must be exercised within the framework of the law. Police were out in force in Beijing and Shanghai on Tuesday to prevent further protests against pandemic restrictions that have disrupted the lives of millions, damaged the economy and briefly led to rare calls for Xi to step down. Hugh Yu, who says he participated in the 1989 Tiananmen Square protests and now lives in Canada, called on Canadians and the Canadian government to speak out against China’s actions. “A lot of people don’t want to die in silence,” he said of protesters in China. “I don’t want to stand here and speak to you guys. But I have no choice.” On Tuesday, China sent university students home and flooded streets with police in an attempt to disperse the most widespread anti-government protests in decades, as the country’s top security body called for a crackdown on “hostile forces”. In an apparent effort to tackle anger at the zero-Covid policies, authorities also announced plans to step up vaccination of older people. Such a move is a vital precursor to loosening controls without mass deaths or overwhelming the health system in a country where there is almost no natural immunity to Covid, after nearly three years of trying to eliminate the virus. China has not yet approved mRNA vaccines, proven to be more efficacious, for public use. National health officials said on Tuesday that China would respond to “urgent concerns” raised by the public and that Covid rules should be implemented more flexibly, according to each region’s conditions. Hours later in Zhengzhou, the site of a Foxconn factory that makes Apple iPhones and has been the scene of worker unrest, officials announced the “orderly” resumption of business, including at supermarkets, gyms and restaurants. However, they also published a long list of buildings that would remain under lockdown. On Wednesday, health authorities in Shanghai ordered subordinate units to stockpile at least 60 days’ worth of anti-epidemic materials, prompting rumours of a pending return to the lengthy lockdown the city was under from March until June. Shanghai Disneyland was closed again on Tuesday, only four days after reopening following a Covid-related shutdown. In a sign of official concern, the Communist party’s central political and legal affairs commission, which oversees all domestic law enforcement in China, met on Tuesday. Its members blamed “infiltration and sabotage” by “hostile forces” and called for a crackdown, according to a readout of a meeting in the state news agency Xinhua. Residents of at least one compound in Guangzhou were allegedly told by building managers that Taiwanese and American-paid trolls had “infiltrated the homeowner [chat] groups of various residential areas, inciting the people to resist the epidemic prevention policy”. Screenshots of the message, seen by the Guardian, warned against attending any protests and urged people to report any neighbours making inflammatory remarks to national security agencies. A resident of that compound said friends elsewhere in the city had received the same message. Chinese authorities often blame discontent on “foreign forces”, although the claim is likely to be shrugged off by many people in China frustrated by the fierce restrictions deployed to try to keep Covid out of the country. One weekend protest video showed a sarcastic crowd asking whether accusations about “foreign forces” referred to Marx and Engels, the fathers of communism, whose works still feature on the Chinese syllabus. The protests appear to have blindsided authorities. The foreign ministry spokesperson, Zhao Lijian, a champion of hyperaggressive “wolf-warrior” diplomacy, was rendered briefly speechless on Tuesday by a question about whether the government would consider changing course on Covid after the demonstrations. China’s zero-Covid policy has helped keep case numbers lower than those of the US and other leading countries, but global health experts including the head of the World Health Organization (WHO) increasingly say it is unsustainable. China dismissed the remarks as irresponsible. Beijing needs to make its approach “very targeted” to reduce economic disruption, the head of the International Monetary Fund (IMF) told the Associated Press in an interview on Tuesday. “We see the importance of moving away from massive lockdowns,” said the IMF managing director, Kristalina Georgieva, in Berlin. “So that targeting allows to contain the spread of Covid without significant economic costs.” Economists and health experts, however, warn that Beijing cannot relax controls that keep most travellers out of China until tens of millions of older people are vaccinated. They say that means zero-Covid controls might not end for another year.