Shanghai and Beijing went back on fresh Covid-19 alert after parts of China's largest economic hub started imposing new lockdown restrictions while the most populous district in the Chinese capital shut entertainment venues.
Both cities had eased widespread Covid curbs recently after a decline in new cases. However, the country has stuck with a "dynamic zero-Covid" policy aimed at shutting down transmission chains as soon as possible.
The sprawling Minhang district in Shanghai, home to more than 2 million people, said it will conduct nucleic acid tests for all residents on 11 June and ordered residents to stay home during the period.
Several other street-level government authorities in other districts of the city have also issued notices saying residents will be subject to two days of confinement and another 12 days of rigorous testing starting from today.
According to notices issued for at least three neighbourhoods, residents must stay indoors until Saturday, and complete five rounds of compulsory tests ending on 23 June.

Many of these were in the central district of Xuhui, where green fences and red wooden boards have sprung up over the past week, barricading residents in and triggering fresh public anger.
A Shanghai government media outlet The Paper said one of the Xuhui outbreaks was traced to a well known beauty salon, the Red Rose, in the city centre which reopened on 1 June when the city-wide lockdown was eased.
Three workers there had tested positive for Covid-19, it said this morning. The shop had received 502 customers from 15 out of the city's 16 districts in the past eight days, it said.
Authorities said a preliminary investigation found that some of the salon's 16 employees did not undergo daily Covid-19 testing as required, and that 90,000 people linked to Red Rose staff or customers had been tested.
"When is this ever going to end?," commented one Weibo user on a media report on the Red Rose. "I just want to have a normal life."
While China's infection rate appears very low compared with many other countries, which have now opted to live with the virus, the government has doubled down on its zero-Covid policy to protect its elderly and its medical system, and has warned that it will not tolerate any comments or actions that doubted or repudiated the policy.
China reported 240 new coronavirus cases on 8 June, of which 70 were symptomatic and 170 were asymptomatic, the National Health Commission said.
Authorities in Chaoyang, a Beijing district of more than 3million people, ordered entertainment venues and internet cafes to shut today, and patrons of four specific bars were told to identify themselves and self-isolate.
Shanghai's two-month lockdown, the shuttering of many malls and venues across Beijing as well as movement curbs imposed in many other Chinese cities in recent months have heavily battered the Chinese economy, disrupted supply chains and slowed international trade.
Authorities have been keen to revive business and started to relax some curbs in May which helped China's exports that month to grow at a double-digit pace, beating expectations.
In Shanghai, China's most cosmopolitan and its biggest business hub, officials have also been trying to mend ties with foreign firms by holding multiple meetings with executives and easing a key border requirement for overseas workers.
The Shanghai Disney Resort, which has been shut since 21 March, said it will reopen some retail and park areas from tomorrow but the main Disneyland park, Disneytown and its two resort hotels will remain closed until further notice.
Several local-level authorities in Shanghai, which is home to 25 million people, have issued notices saying residents will be subject to two days of confinement and another 12 days of rigorous testing from today.
Many of the notices were in the central Xuhui district, where green fences and red wooden boards have sprung up in the past week, barricading residents in and triggering fresh public anger.
Business chambers said uncertainty surrounding Covid-19 restrictions remained a key concern for foreign firms.
"This unpredictability, and increased risk, is resulting in many businesses delaying, reducing or withdrawing entirely from the Chinese market," said Alexandra Hirst, senior policy analyst with the British Chamber of Commerce in China.
"The business climate is not positive because despite the fact that the cities opened, there is still the problem of the zero-Covid policy," Christophe Lauras, president of the French Chamber of Commerce in China, told Reuters.
"That is to say that every morning people don't know if they'll be locked down," he said.
Meanwhile in the US, President Joe Biden has said he is "not too worried" about the slow pace of pre-orders of Covid-19 vaccines for children.
His administration said that they expect the pace to pick up after expected approvals from the Food and Drug Administration and the Centers for Disease Control and Prevention later this month, with vaccinating to begin as early as 21 June.
The vaccines will be distributed to pediatricians, children's hospitals, local pharmacies and local health clinics, officials said.
The administration has allowed states and others to pre-order from an initial batch of 5m Moderna and Pfizer vaccines (2.5 million each) but thus far, 58% of the available 2.5 million Pfizer vaccines have been ordered and just 34% of the Moderna vaccines, officials said.
"Our experience has been that people are slow to order and this has been true across each of the times we've opened up ordering.
"We're not too worried or focused on that. We'll continue to do the outreach."
In most parts of the world, no Covid-19 vaccine has yet been approved for children in the 5-and-under age group and so it remains unclear how many parents will get their children vaccinated.