The country has seen 377 cases of COVID-19 between October 17-29, according to National Health Commission (NHC) data.
At the time of writing, China has reported 72 cases of COVID-19 in the last 24 hours, according to the World Health Organization, representing a 70% increase in the virus diagnosis.
This outbreak is concentrated in the northeast of the country, caused by a virus carrier arriving from abroad, the NHC said, last week.
Heihe, a city of 1.3 million people, reported 26 local cases for October 29, compared to nine on October 28 and one on October 27.
"Within the past 14 days, 14 provincial areas have reported new locally transmitted cases or asymptomatic carriers," the NHC spokesperson Mi Feng said on Saturday, Reuters reported.
"The outbreak is still developing rapidly, and the virus control situation is severe and complicated," he continued.
Wu Liangyou, another NHC official, added that the outbreak depicted a "laxity of mind" among local authorities, urging for strengthened screenings for the virus.
Although significant measures are being taken, including canceling the Beijing marathon, the numbers are still relatively small compared to other countries.
On October 24, the NHC warned of the further spread of the virus across the country.
Mi Feng warned of "seasonal factors" worsening the spread of the virus, Reuters reported.
Though the outbreak is dwarfed by the number of cases in other countries, Beijing would not want a COVID-19 spike to jeopardize the 2022 Winter Olympics.
Chinese athletes will require a vaccine booster shot, while foreign athletes are recommended to get a booster shot but it is not compulsory, according to a state TV report, Reuters said.