Shanghai authorities were tightening the city-wide Covid lockdown they imposed more than a month ago, prolonging into late May an ordeal that China's capital Beijing was desperate to avoid by turning mass testing into an almost daily routine.
The commercial hub of 25 million was making a fresh push to bring case numbers outside the areas that were facing the strictest curbs to zero by the second half of May, people familiar with the matter told Reuters.
The people said movement curbs will generally remain through the month due to fears of a rebound even though case numbers have been falling. Authorities in some districts issued notices ordering people back into their residential compounds after having let them out for brief walks or quick shopping.
In a video shared widely on Chinese social media, police in hazmat suits argue with residents who were told they needed to be quarantined after a neighbour tested positive.
"This is so that we can thoroughly remove any positive cases," one of the officers is heard saying. "Stop asking me why, there is no why. We have to adhere to national guidelines."
Reuters was not able to independently verify the video.
The Shanghai government did not immediately respond to a request for comment.
The prolonged isolation and fear of being sent to quarantine centres, which sometimes lack showers and other basic conditions, have caused widespread frustration, even altercations.
Videos posted online last week showed dozens of workers at Apple and Tesla supplier Quanta overwhelming hazmat-suited security guards and vaulting over factory gates to escape being trapped inside amid Covid rumours.