More than 11,000 recovered Covid-19 patients were discharged in Shanghai on Sunday, and health authorities emphasised that they must be allowed to return home despite the lockdown that has severely restricted movement in China’s largest city. “We hope their family and community will not worry about them or discriminate against them,” said Wu Jinglei, the director of the Shanghai municipal health commission. The city of 26 million people reported 1,006 confirmed infections and almost 24,000 asymptomatic cases over the previous 24 hours. Shanghai has been under lockdown since 28 March, and authorities said on Saturday that the strict measures would be lifted in areas with no new cases in the last 14 days following another round of mass testing. The US advised its citizens on Saturday to reconsider travelling to China, because of the “arbitrary enforcement” of local laws and Covid-19 restrictions, particularly in Hong Kong, Jilin province and Shanghai. US officials cited a risk of “parents and children being separated”. The Chinese foreign ministry spokesperson, Zhao Lijian, said in response that China was “strongly dissatisfied with and firmly opposed to the US side’s groundless accusation against China’s epidemic response. “It should be pointed out that China’s anti-epidemic policies are science-based and effective, and we are fully confident that Shanghai and other places in China will prevail over the new wave of the epidemic,” Zhao said. Meanwhile, Shanghai authorities said they have secured daily supplies for residents from online platforms, according to the state-owned newspaper Global Times, following complaints about deliveries of food and other basic necessities as the lockdown enters its third week. Residents have resorted to group-buying groceries because they are not allowed to leave their buildings. Posts circulating on social media platforms such as Weibo also showed that some residents have not been able to have their food orders delivered, while others posted online that they were running out of food. Some people said that as soon as they went to the grocery shopping app, a day’s orders were already filled. According to the Global Times, platforms with delivery apps, including JD.com and Alibaba’s Ele.me, were working with authorities to ensure that everyone has access to vegetables, fruit and other produce. The situation in Shanghai highlights the soaring human and economic cost of China’s “zero-Covid” strategy, which aims to isolate every infected person. Meanwhile, Erjiefang, an area in the capital, Beijing, was classified as high-risk on Saturday after eight Covid-19 infections were reported there over the past two weeks. In Guangzhou, primary and middle schools will switch to online learning from Monday after the city of 18 million north-west of Hong Kong registered 23 local infections since Friday, the official Xinhua news agency reported. An exhibition centre was being converted into a makeshift hospital after authorities said earlier they would begin mass testing across the city. China has faced some of its worst local outbreaks since the pandemic began, and the country remains closed to international travel, even as most of the world has sought ways to live with the virus.