China's financial hub Shanghai reported over 27,000 cases of coronaviruses, setting a new record.
On Thursday, Shanghai reported a record 2,573 total symptomatic cases for the previous day, up from 1,189 a day earlier.
Asymptomatic cases, for example, reached 25,146, up from 25,141.
The numbers came a day after President Xi Jinping said the country must continue with its strict COVID clearance policy and pandemic control measures.
Since the virus first appeared in Wuhan in late 2019, Shanghai is battling China's worst COVID 19 outbreak.
The city's 25 million residents are largely under lockdown, though restrictions were partially eased in some areas this week.
On Wednesday, the Chinese Center for Disease Control and Prevention published a guide on home quarantining on its social media, which raised hopes for a change in policy.
Even people with symptoms must go into quarantine at centralised facilities, where many people complain about poor conditions under China's tough rules.
The CDC's guide on quarantine at home — in a well-ventilated room stocked with masks, sanitiser and other gear — raised hopes that the rule for quarantine at state facilities might be relaxed.
When asked in an online comment section about who might be eligible for home quarantine, the CDC referred to the old rules.
The Shanghai authorities did not give any hint of any change in approach during the Thursday briefing.
A city official said cases continued to rise despite the lock down, in part due to a backlog of test results and ongoing transmission among family members.
On Wednesday, Mr Xi said that China must stick to its strict COVID clearance policy while the global epidemic remains very serious, promising that enduring lockdowns will win out in the end.
During a visit to South China's Hainan island, Mr Xi indicated that there would be no immediate change to approach in pandemic control measures.
He said the country must adhere to its approach, which has all but shut China's borders to international travel, and not relax preventive measures.
China has a zero-COVID policy that has been challenged by the fast-spreading Omicron variant, which has put millions of people under lockdown and disrupting supply chains.
Although the virus is still spreading, other countries have thrown off restrictions.
An April 7 study by Gavekal Dragonomics found that 87 of China's 100 largest cities by GDP have imposed some form of quarantine curbs.
On Thursday, authorities in the north-eastern province of Jilin said they had stamped out local spread of COVID 19 after battling to bring down cases since mid-March.
After quashing its own outbreak last month, the southern tech hub of Shenzhen appeared to be seeing a resurgence.
The highest total for new infections since March 21 was reported by authorities on Thursday, including 8 with symptoms and 13 without.