Shanghai reported three new local COVID-19 infections outside its quarantined population on Tuesday, the city's health commission said.

The three cases were all asymptomatic and discovered through regular screening, two in Yangpu district and one in the city's suburban Jinshan district.

The neighborhoods where the three cases live were added to the city's list of medium-risk zones, of which there are currently 21.

Shanghai experienced a wave of new local infections outside its quarantined population during the first two weeks of October involving mostly inbound visitors or returning residents.

The city had not reported new local infections among its non-quarantined population for more than one week before Tuesday.

To ensure its epidemic prevention and control, Shanghai authorities also announced earlier in the day the normalized nucleic acid test sites across the city will extend their services for free through the end of November.