TIANJIN -- North China's Tianjin municipality will launch the fourth round of citywide nucleic acid testing at 6 am Thursday, said the municipal epidemic prevention and control headquarters.

The mass testing, with the aim to protect people's health, curb the further spread of the epidemic and reinforce the existing outcome, is scheduled to be completed in about 24 hours, it added.

The municipality of 13.9 million people that neighbors Beijing has conducted three rounds of citywide mass testing since Jan 9.

The infections in the latest resurgence in Tianjin were first reported on Jan 8, and the gene sequencing found the first two locally transmitted confirmed cases were the VOC/Omicron variant.

As of Monday, a total of 312 locally transmitted confirmed COVID-19 cases and 22 asymptomatic cases have been detected in this resurgence that started on Jan 8.