But he added that despite the "gnarly" headlines, the rise could be the result of a testing backlog being cleared over the weekend in Hubei province, where the virus emerged late past year.
But the World Health Organization warned it was too soon to declare victory.
"We'd like to be able to predict the future, but we must be cautious", said Mike Ryan, the executive director of WHO's health emergencies program.
Shanghai Mayor Ying Yong has been appointed as the new secretary of the Hubei Provincial Committee of the Communist Party of China, replacing Jiang Chaoliang, the official Xinhua news agency said without explaining why Jiang was removed.
Hundreds of military medics will descend on coronavirus-stricken Wuhan to help tackle the epidemic as the number of confirmed cases worldwide surpasses 60,000, with the death toll leaping over 1,300.
The new system means doctors can use lung imaging, rather than exclusively laboratory tests.
Wednesday's report marked the highest infection and death count in a single day since the outbreak began.
Authorities in Hubei have been accused of concealing the gravity of the outbreak in early January because they were holding key political meetings at the time.
Analysts have said that the initial delay in raising the alarm in Wuhan may have arisen from local officials' fear of bringing bad news to the attention of the central government, especially as Lunar New Year festivities approached.
Hubei's two top health officials were fired earlier this week. Chinese officials said the method is only being used in Hubei.
"Oddly, this now is a moment of greater transparency", Sam Crane, political science professor at Williams College in MA, told AFP. Experts say an epidemic in North Korea could be dire because of its chronic lack of medical supplies and poor health care infrastructure. "They're talking about using this as another diagnostic test, but we haven't seen it validated by data", Schaffner said.
"We have to use the current window of opportunity to hit hard and stand in unison to fight this virus in every corner", he said Tuesday, on the first day of an global scientific conference in Geneva that will look at possible vaccine options to combat the virus.
In Vietnam, authorities announced they were locking down the commune of Son Loi, a farming region about 40 kilometers (25 miles) from Hanoi, for 20 days. Health officials wearing protective suits sprayed disinfectant on vehicles.
The total now includes more than 13,000 cases of "clinical diagnosis" in Hubei, which appears to include those based on a doctors' analysis combined with lung imaging, as opposed to waiting for laboratory test results.
Several countries have banned arrivals from China, while major airlines have halted flights to and from the country.
United Airlines UAL.O said it would extend cancellations of all USA flights to China through late April, meaning all US passenger carriers flying to China had now canceled flights into late April. But an accurate grasp of the situation within China is necessary for the safety of the rest of the world, noted Tedros of the WHO.