QINGDAO, Sept. 26 (Xinhua) -- A total of 12,492 people working at the Qingdao Port had been tested for nucleic acid as of Friday after two stevedores were reported as asymptomatic COVID-19 cases on Thursday.

All test results were negative and testing for the remaining personnel is underway, according to the port in east China's Shandong Province Saturday. Around 20,000 people work in the port area.

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

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

A total of 1,440 samples taken from the cold chain products and the surrounding environment have been collected and tested, and 51 samples have tested positive, said the commission on Friday.

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