China's northeastern port city of Dalian has sampled over 4.75 million people for nucleic acid tests in a citywide health screening in the wake of newly emerged COVID-19 cases, local authorities said Friday.

Over 3.13 million of them have tested negative and the rest of the results are yet to arrive, according to the municipal health commission.

As of Thursday, Dalian had reported a total of 19 confirmed cases of COVID-19 since four cold-chain workers first tested positive on December 15. The city started to conduct tests on all its citizens on Tuesday.