By Martin Quin Pollard and Engen Tham
BEIJING/SHANGHAI (Reuters) - The Chinese capital extended its work-from-home requirement for many of its 22 million residents to stem a COVID-19 outbreak, while Shanghai deployed more testing and curbs to hold on to its hard-won "zero COVID" status after two months of lockdown.
Beijing said 99 new cases were detected on Sunday, up from 61 the previous day - the largest daily tally so far during a month-old outbreak that has consistently seen dozens of new infections every day.
"(Beijing) should fully implement the requirement of working from home in key areas, further lower the rate of working from the office to reduce the flow of people and quieten the community," Xu Hejian, spokesman for the Beijing municipal government, told a news briefing.
The capital must "hold every line of defence" against new cases, he said.
Six of the city's 16 districts have told all residents to work from home and avoid gatherings, and said those who have to go to work should have a negative PCR test taken within 48 hours. A further three encouraged certain groups to follow such measures, with each district responsible for implementing its own guidelines.
Offices in areas following the working-from-home guidance must not exceed 30% capacity.
Despite the ominous milestone in the capital, health officials said that infections in China, where COVID-19 was first detected in late 2019 in the central city of Wuhan, show a steady declining trend.
Analysts at Gavekal Dragonomics estimated last week that fewer than 5% of Chinese cities were reporting infections, down from a quarter in late March, in an outbreak that has cast a pall over the world's no. 2 economy.
In Shanghai, fewer than 600 daily cases were reported for Sunday, with none outside quarantined areas, as has been the case for much of the past week.
The commercial hub of 25 million reopened more than 250 bus routes and a small part of its sprawling subway system on Sunday. But many towns and districts announced more mass testing and asked residents not to leave their compounds.
In the city's Changning district, one neighbourhood committee worker walked around with a loudhailer playing on repeat: "Residents, during the epidemic, do not go out unless for essential reasons!
"Wear a mask if you do go out, do not gather with others to smoke or to chat. And remember to wash your hands when you return home and take an antigen test."
Shanghai has allowed more people to leave their homes for brief periods over the past week, although it generally plans to keep most restrictions in place this month, before a lifting its two-month-old lockdown from June 1.
Beijing had already curtailed public transport, asked some shopping malls and other stores and venues to close and sealed buildings where new cases were detected.
In one large residential compound not under isolation orders, shelves have been set up for deliveries at the entrance, according to residents, fuelling fears that tougher controls were on the way.
The curbs in Beijing, Shanghai and elsewhere in China are leaving behind significant economic damage and disruption to global supply chains and international trade.
China's blue-chip CSI300 index closed down 0.6% on Monday. The benchmark has shed 18% this year, according to Refinitiv data.
The highly transmissible Omicron variant has proven hard to defeat even with strict measures that starkly contrast the resumption of normal life elsewhere in the world.
"We've been massively hit," said a convenience store owner surnamed Sun, whose shop in Beijing has only been allowed to operate during daytime rather than its usual 24/7 hours.
"Even during the Wuhan outbreak we could stay open the whole time."
While more people are being allowed outside in Shanghai, several residents said they had been told of infections in their vicinity that required new curbs on movement.
One resident in Hongkou district, which has not reported any new community-level cases since May 7, said he was told last week not to leave his flat, having been allowed to move within his compound previously.
Hongkou was among six districts which have announced some tightening of curbs in recent days to "consolidate" the results of their efforts so far.
But such moves made some people fear the virus was making a comeback.
The top comment on a post by state agency Xinhua on China's Twitter-like Weibo on Shanghai's latest numbers read: "This can't be accurate, zero COVID cases at community level? Our compound had one new case yesterday."
Asked to comment, the Shanghai government said that all cases found in recent days were in "sealed" high-risk areas or quarantine centres and that any community transmission cases would be announced on official channels.
(Reporting by Martin Quin Pollard, Roxanne Liu, Engen Tham, Winni Zhou and Brenda Goh and the Beijing and Shanghai bureaus; Writing by Marius Zaharia and John Geddie; Editing by Kenneth Maxwell and Nick Macfie)