QINGDAO -- A total of 139,658 people in Qingdao, East China's Shandong province, have been given nucleic acid tests for COVID-19 and returned negative results, after two stevedores working at the Qingdao Port were reported as asymptomatic COVID-19 cases on Thursday.

The municipal government issued the data at a press conference on Saturday afternoon, saying that testing of the remaining personnel is still ongoing.

As of 8 am Saturday, the city had combed 209 close contacts of the two workers, all of whom have been placed in quarantine and under close observation, while a second round of testing among the contacts is underway.

Around 20,000 people work in the port area, and as of Friday, 12,492 of them had tested negative.

The two workers, aged 40 and 45, had both handled imported frozen seafood on Sept 19. Nucleic acid tests on Thursday revealed the two were positive for novel coronavirus.

The municipal health commission said the batch of imported products had not yet entered the market and has been sealed.

A total of 21,271 samples from the city's cold chain products and environment have been tested, with 51 samples from the port testing positive, said Zhang Huaqiang, deputy director of the city's disease control and prevention center at the press conference.

An emergency response plan has been activated and the overall operation of the port remains normal.