(Bloomberg) -- Beijing reported a record number of Covid cases during its current outbreak, reviving concern the capital may face a lockdown as authorities seek to stamp out community spread of the virus.

The city reported 99 cases for Sunday, up from 61 on Saturday. While the total is still low, the spike is one of the biggest since the outbreak started, with the case tally mostly hovering around 50 a day. 

On the weekend, authorities reiterated that residents in five areas, including the Chaoyang central business district and the Haidian technology hub, should work from home through May 28. All residents of a large housing complex were sent to quarantine after 26 cases were discovered in the compound, the Beijing Youth Daily reported on Saturday. 

Shanghai reported 558 cases on Sunday, down from 622 on Saturday. No new infections were found outside of government quarantine. 

Shanghai authorities on Sunday laid out the criteria it would use to categorize parts of the city as low-risk for Covid as they look to end a grueling two-month long lockdown. From June, districts that haven’t reported positive cases or community infections for 14 days will be defined as low-risk. Residents in high- and medium-risk areas will be restricted to their homes and be required to take a PCR test daily for 14 days.

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