A medical worker collects a swab sample of a student for nucleic acid testing at a primary school in Lu'an, east China's Anhui Province, May 17, 2021.

The Chinese mainland on Tuesday reported 13 newly confirmed COVID-19 cases, including one locally transmitted cases and 12 arriving from outside the mainland, the National Health Commission said Wednesday.

The locally transmitted case was reported in Guangdong Province, the commission said in its daily report.

Of the imported cases, six were reported in Shanghai, two in Sichuan, one each in Jiangsu, Zhejiang, Fujian, Shaanxi.

There were 290 active imported cases as of Tuesday. No deaths related to the disease were reported, while 12 COVID-19 patients were discharged from hospitals.

The total number of confirmed cases on the Chinese mainland stood at 91,019, with the death toll unchanged at 4,636.