The city, which is about an hour’s ride by train from capital Beijing, has been under a de facto state of emergency since the beginning of the week over an uptick in the number of COVID-19 cases.

"The city of Shijiazhuang is conducting citywide COVID-19 tests, and all the vehicles and people in the city are not allowed to leave," Deputy Mayor Meng Xianghong said during a press conference, as quoted by state media.

Health authorities have registered 50 cases on Thursday alone as a result of the mass testing drive, rendering it the largest outbreak since the original outbreak in Wuhan died down in April of last year.

Most flights to and from the city have been canceled while inter-city train stations have been shut down.

Chinese authorities have maintained a high vigilance to avoid falling into a new wave of coronavirus transmissions. Authorities in June shut down an entire district of Beijing when local transmissions were detected at a seafood market.

China’s tight lid on the coronavirus and relatively swift return to normal life may see it become the only major economy to grow in 2020, something that will be clear once fourth-quarter figures are in.