China reported 17 new coronavirus cases on Sunday, the second day in a row new cases were in the double digits.
Three cases were in Shulan, a city near the Russian and North Korean border that's been reclassified as a high-risk region.
Wuhan, the original coronavirus epicenter, reported six new cases over the weekend, all in one neighborhood.
A party secretary in Wuhan was fired over his "poor control of the disease," according to the South China Morning Post.
Two new clusters of coronavirus cases in China have been reported hundreds of miles apart, sparking fears of another large-scale outbreak.
On Sunday, the country's National Health Commission reported 17 new coronavirus diagnoses, the highest number in almost two weeks, and the second day in a row new cases were in the double digits, Reuters reported.
Fourteen cases were in Shulan, a city of more than 700,000 near the Russian and North Korean borders. They were all traced to a 45-year-old woman working at a police laundry department with no history of recent travel or contact with an infected person.
The government has reclassified Shulan as a high-risk region, the only city in China with that classification. Authorities have closed public spaces, with residents told to stay home unless there were "unusual circumstances."
"We're now in a 'wartime' mode," Shulan Mayor Jin Hua said on Monday, adding that the city would be in lockdown until the end of May and testing for residents would increase. In addition, anyone who returned from abroad also would be tested.