A news outlet operated by the ruling Communist Party in Qingdao on Friday reported the municipal health chief as saying that the eastern city was seeing "between 490,000 and 530,000" new Covid cases a day.
The coastal city of around 10 million people was "in a period of rapid transmission ahead of an approaching peak", Bo Tao reportedly said, adding that the infection rate would accelerate by another 10 percent over the weekend.
The report was shared by several other news outlets but appeared to have been edited by Saturday morning to remove the case figures.
China's National Health Commission said Saturday that 4,103 new domestic infections were recorded nationwide the previous day, with no new deaths.
In Shandong, the province where Qingdao is located, authorities officially logged just 31 new domestic cases.
China's government keeps a tight leash on the country's media, with legions of online censors on hand to scrub out content deemed politically sensitive.
Most government-run publications have downplayed the severity of the country's exit wave, instead depicting the policy reversal as logical and controlled.
But some outlets have hinted at shortages of medicine and hospitals under strain, though estimates of actual case numbers remain rare.
The government of eastern Jiangxi province said in a Friday social media post that 80 percent of its population -- equivalent to around 36 million people -- would be infected by March.
More than 18,000 Covid patients had been admitted to major medical institutions in the province in the two weeks up to Thursday, including nearly 500 severe cases but no deaths, the statement said.
'No historical precedent'
There were signs that medical resources remained under stress as the weekend began, as some regional health officials warned that the worst was yet to come.
The southern manufacturing hub of Dongguan said Friday that outbreak modelling indicated up to 300,000 new infections per day, adding that the rate was "accelerating faster and faster".
"Many medical resources and personnel are enduring severe challenges and huge pressure with no historical precedent," read a statement issued by the health bureau of the city of 10.5 million.
The bureau also published a video showing patients connected to intravenous drips queuing outside a clinic, and a doctor sleeping on his desk after working late into the night for several days straight.
A senior health official in Hainan said Friday the island province would reach peak infections "very soon", while in the eastern megacity of Shanghai more than 40,000 patients were treated for "fevers", the state-run People's Daily newspaper reported Saturday.
Authorities in Chongqing launched a campaign to inoculate residents with inhalable vaccines as the central megacity grapples with a significant outbreak.
AFP journalists in the city of 32 million this week witnessed hospitals overflowing with mostly elderly Covid-positive patients, and dozens of bodies being unloaded at crematoriums.