SHANGHAI - Shanghai on Saturday launched a new round of city-wide screening using both nucleic acid and antigen testing amid its latest efforts to contain the COVID-19 outbreak.

The tactic comes at a time when the city seeks to tame a surge in COVID-19 cases. On Friday, the city reported 38 local confirmed COVID-19 cases and 2,231 asymptomatic carriers.

Health authorities started using differentiated screening tactics in all the sub-districts and townships according to their risk levels to find all infections and stop the transmission in communities, said Wu Jinglei, director of the Shanghai municipal health commission.

Nucleic acid screening applies to key areas in the outbreak, totaling 23 sub-districts, while antigen testing applies to non-key areas, Wu told a press conference Saturday.

Local authorities are imposing closed management over the key areas where people are banned from going out before the results of their nucleic acid testing come out.

Local authorities have renovated seven venues, including hospitals and stadiums, to quarantine mild cases and asymptomatic carriers, according to Wu.

He also ordered hospitals to take scientific and targeted control measures to reduce the impact on the availability of medical services to other sick people.