Xi'an started a new round of nucleic acid testing at 12 am on Monday and tightened its policy of lockdown by requiring all its residents to stay at home to guarantee the accuracy of the test results.
In a news conference on Monday afternoon, Shaanxi government said that newly reported cases may continue to emerge in the following days with possible sporadic flare-ups.
The complete genome sequencing of 137 locally transmitted cases shows that the virus strain is highly similar to with the one identified in an imported case from Pakistan on December 4, local officials added.
Xi'an has been locking down its communities since Thursday, but each family could send one person outside once every two days to purchase daily necessities during the past days.
Local government said that it would tighten controls to minimize the flow and movement of local people before the test is finished, and adjust the prevention measures depending on the testing results.
Chen Zhijun, deputy director of Xi'an Municipality Center for Disease Control and Prevention, told the media on Sunday evening that the requirement to stay indoors was raised given that quite a few silent carriers haven't been detected yet.
Local residents will likely get infected if they come in contact with each other in short distance without proper prevention measures, Chen said.
The Chinese mainland on Monday reported 182 new locally transmitted COVID-19 cases, the National Health Commission said in its daily report on Tuesday.
Of the new local cases, 180 were reported in Shaanxi, and one each in Zhejiang and Yunnan, the commission said.
Also reported were 27 new imported cases in 10 provincial-level regions, according to the commission.