Rui Baoling, head of the city's disease control and prevention center, said the center has implemented a mixed sampling method, which puts the samples from the upper respiratory tracts of five people into one sampling tube for the laboratory test.

"The method was taken in order to further improve the ability and efficiency of the test, and during the test, we will pay special attention to the registration of personal information," Rui said.

Rui said if a positive result is found in the mixed sample, the center will quickly find the group of five people for resampling and screening.

Meanwhile, to ensure the smooth and orderly supply of daily needs, Urumqi has set up more than 2,000 temporary food and service centers for people who have had to stay at home.

"We will purchase whatever the residents need," said Adil Abduraxt, deputy director of a residential community in Tianshan district.

New case in Dalian

Also on Wednesday, Dalian, a coastal city in Liaoning province, reported a locally transmitted COVID-19 case, according to China Central Television.

The patient, surnamed Shi, 58, is an employee of a seafood processing company in the city who lives alone in Xigang district. He developed symptoms including fever and fatigue on July 16 and went to hospital for treatment on Tuesday. He tested positive on Wednesday morning and was sent to a hospital designated to treat COVID-19 cases. All of his close contacts have been quarantined.