The Chinese city of Wuhan conducted more than 6.5 million novel coronavirus tests in just 9 days, according to state media, a drastic move by authorities to prevent a second wave of infections in the original epicenter of the global pandemic, CNN reports.

Wuhan's ambitious citywide nucleic acid testing drive came after six new cases emerged in a residential community earlier this month -- the first time local infections were reported following the city's emergence from its months-long lockdown in April.

From May 15 to May 23, swab test samples were collected from more than nine million residents, China's state-broadcaster CCTV reported, accounting for more than 80% of the city's total population of 11 million.

Nucleic acid tests work by detecting the virus' genetic code, and can be more effective at detecting the infection, particularly in the early stages, than tests which examine a body's immune response, though the latter are easier to conduct. The mass testing identified 198 asymptomatic cases -- people who carry the virus but do not show symptoms, according to the state-run Health Times.

The speed and scope of Wuhan's testing campaign -- hailed as a "10-day battle" by local authorities -- appears to have equaled or eclipsed the testing ability of many countries, including that of the United States. On Friday alone, Wuhan conducted 1.47 million tests, according to CCTV.