ZHENGZHOU - The central Chinese city of Zhengzhou, capital of Henan province, further tightened epidemic prevention and control measures after a recent resurgence of COVID-19 infections, according to local authorities on Thursday.

The city classified 15 new areas as medium-risk for COVID-19 on Thursday, and began its second round of nucleic acid testing at 9 am Thursday and will complete the sampling process at 5 pm Friday.

According to education department, the city's primary school enrollment has been postponed.

Henan reported 21 locally transmitted confirmed COVID-19 cases and 102 asymptomatic cases from July 31 to August 5 in the latest resurgence of COVID-19, the provincial health commission said Friday.