Shanghai health authorities have discharged more than 11,000 recovered Covid-19 patients 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, director of the Shanghai Health Commission, on Sunday.

The city of 26 million people reported 1,006 confirmed infections and nearly 24,000 asymptomatic cases in the last 24 hours. Shanghai has been under lockdown since March 28, 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 United States on Saturday advised its citizens to reconsider traveling to China due to “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”.

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,” said Zhao.

Meanwhile, Shanghai authorities said that they have secured daily supplies for residents from online platforms, according to 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 of groceries because they are not allowed to leave their buildings. Posts circulating on social media platforms such as Weibo also show that some residents have not been able to have their food orders delivered, while others posted online that they are running out of food.

Some people said that as soon as you go to the grocery shopping app, a day’s orders are already filled.

According to the Global Times, platforms such as JD.com as well as Alibaba’s Ele.me delivery apps are working with authorities to ensure that everyone has access to vegetables, fruits and other produce.

Shanghai highlights the soaring human and economic cost of China’s “zero-Covid” strategy that aims to isolate every infected person.

Separately, Erjiefang, an area in the capital Beijing, was classified as high-risk on Saturday after eight local Covid-19 infections were reported there over the past two weeks.

And in Guangzhou, primary and middle schools will switch to online learning starting on Monday after the metropolis 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 citywide mass testing.

China is facing one of its worst local outbreaks since the pandemic began. China is still closed to international travel, even as most of the world has sought ways to live with the virus.