QINGDAO, Oct. 16 (Xinhua) -- Qingdao, a coastal city in east China's Shandong Province, has completed a citywide nucleic acid testing covering all its 11 million residents starting Monday, after a new cluster of local COVID-19 infections emerged.

As of 6 p.m. Friday, all of the over 10.89 million collected samples had been tested, and results showed no new positive cases, according to the municipal government.

The re-emerged infections have led to 13 new confirmed cases by Thursday. Inappropriate disinfection in the CT room at the Qingdao Chest Hospital was believed to be responsible for the infections.