Shanghai added three new locally transmitted asymptomatic COVID-19 cases on Saturday, the municipal government said on Sunday.

All the three asymptomatic cases were close contacts of either a local confirmed case or local asymptomatic case reported in Shanghai on Thursday, and tested positive for the virus during quarantine.

Shanghai reported two local confirmed cases and three asymptomatic cases on Thursday. The source of their infections was an imported case who arrived in Shanghai on Dec 21.

The disease control and prevention work has tracked down 22 close contacts of the three newly reported asymptomatic cases, aged 24, 25, and 27, respectively. All the public venues related to the cases have been disinfected.

Also, Shanghai reported 24 imported confirmed cases and two imported asymptomatic cases on Saturday. The number of imported cases currently receiving medical treatment in Shanghai has reached 436.

"Both the surge of the COVID-19 spread sweeping many parts of the world related to the Omicron variant and the upcoming Spring Festival have pushed up the number of imported cases to Shanghai, which receives a large ratio of the country's inbound passenger flights, since late December," said Wu Fan, a core member in Shanghai's expert team of COVID-19 fight and vice-dean of Fudan University Shanghai Medical College, at a municipal press briefing on Thursday.