Shanghai continued with the mass testing of millions of residents on Thursday as 322 new confirmed cases and 19,660 asymptomatic carriers were reported, according to the city's health authority.

"Today, we will continue to carry out nucleic acid and antigen testing across the city to detect cases and deploy control measures as early as possible," Wu Qianyu, a senior inspector with the municipal health commission, said at a news conference on Thursday.

Wu said around 150,000 close contacts have been identified and placed under quarantine.

Shanghai has entered the seventh day of a citywide lockdown to contain its worst COVID-19 outbreak which has resulted in more than 100,000 local infections since March 1.