Medical institutions in Dalian, Northeast China's Liaoning province, have immediately entered "a state of war" for epidemic prevention and control, and more than 810,000 people in Dalian Jinpu New Area have been tested for novel coronavirus, an official with the city's health commission said at a news conference on Sunday.

A total of 813,504 samples were collected from all residents for nucleic acid testing in Jinpu. Among them, 192,567 have tested negative, though more remained to be returned, said Zhao Lian, deputy director of Dalian's health commission.

The port city reported a new confirmed case on Saturday. The 39-year-old man tested positive while being quarantined as a close contact of a previously identified asymptomatic case. He is the owner and chef of a restaurant in Xianjin Street, Jinpu, said Zhao.

The residential area where the man lives was classified as a COVID-19 medium-risk area on Saturday following approval by the Liaoning provincial headquarters office for coordinating COVID-19 prevention and control and economic and social development.

Since the port city reported its first four asymptomatic cases on Tuesday, as of Saturday, a total of two confirmed cases have been reported in Dalian, and six asymptomatic cases are under medical observation.

All patients are in stable condition and have been isolated and treated in the city's designated hospital for centralized treatment of COVID-19, Zhao said.

Various levels of the city's medical institutions have immediately entered "a state of war" for epidemic prevention and control. They are asked to strengthen pre-examination triage management with the highest standards, and conduct the most stringent control of personnel entering medical institutions.

Hospital infection should be resolutely avoided. Medical institutions without a fever clinic are strictly prohibited from receiving patients with fever, Zhao said.

The city organized 2,500 medical workers from more than 20 hospitals to move into the streets and communities of Jinpu New Area, quickly set up 500 collection points, and dispatched local testing institutions and third-party medical institutions to transfer samples and test samples in a timely manner.

Meanwhile, Dalian comprehensively strengthened prevention and control of cold-chain frozen products to realize closed-loop management of the whole chain, from port to cold storage.

It also comprehensively strengthened management of people engaged in the cold-chain sector. Front-line personnel in cold storage shall live in a fixed location. Nucleic acid testing shall be conducted at least once a week for people involved and the environment they are in.

The city also is focusing on cafeterias, enterprise's refrigerated warehouses, farmers' markets and other key places to prevent the occurrence of clustered epidemics.