Residents in the Jiangbei New Area, Nanjing City, lined up to take nucleic acid tests as the capital of east China's Jiangsu Province reported nine confirmed COVID-19 cases on Wednesday. /CFP

Seventeen people have tested positive for COVID-19 in the city so far, with nine cases classified as confirmed, five identified as asymptomatic and the remaining three awaited confirmation tests, Deputy Major Hu Wanjin told media at a press briefing on Wednesday afternoon. /CFP

The 17 people are all cleaning staff at Nanjing Lukou International Airport. Hu said authorities had traced 157 close contacts of the confirmed cases. /CFP

Four areas in the city's Jiangning District, where the airport is located, heightened their COVID-19 risk levels from low to medium on Wednesday, according to the municipal government. A mass nucleic acid testing campaign is being conducted across the district. /CFP