Dalian, Liaoning province, is expanding its quarantine range to contain the spread of the novel coronavirus, with around 3 million residents having been tested as of Tuesday morning, a health official said at a news conference.

"Thirty-seven medical observation points have been quarantined," said Zhao Lian, deputy director of the Dalian Health Commission.

Contact tracing had determined that recent confirmed cases and asymptomatic carriers were associated with Dalian Kaiyang World Seafood Co, Zhao said, adding that the city will learn from Beijing's experience in dealing with the cluster of cases related to its Xinfadi wholesale market.

"While quarantining the close contacts of those confirmed with the coronavirus, we will also identify their close contacts and quarantine them also to cut the transmission chains," Zhao said.

She said Dalian had identified six new COVID-19 infections as of Monday, lifting the total number of confirmed cases with symptoms to 44 since a new outbreak discovered on July 22.

All patients are in stable condition and being treated at Dalian Sixth People's Hospital, she said.

Dalian announced on Sunday that it would arrange free coronavirus tests for all residents — around 7 million. Zhao said that as of Monday, 2.96 million samples had been collected, with 2,069 collection sites set up and 8,107 medical workers dispatched to do the work.

Dalian has further enhanced its sampling and testing capabilities, mobilizing 11 laboratories to process tests at full capacity to ensure rapid results.