HOHHOT -- The border city of Manzhouli in North China's Inner Mongolia autonomous region reported five confirmed locally transmitted COVID-19 cases from 12 am to 2 pm on Sunday, local authorities said.

So far, the city has reported 332 locally transmitted confirmed COVID-19 cases in the latest outbreak. All cases are receiving treatment at a designated local hospital, according to a press briefing.

An epidemiological investigation is underway. As of 2 pm on Sunday, a total of 9,229 close contacts and 3,405 secondary close contacts had been placed under medical observation at designated locations.

Health authorities in Manzhouli have completed the seventh round of citywide nucleic acid testing, detecting 47 positive cases among 183,831 samples. The city launched its eighth mass testing at 8 am on Sunday.