Mainland China on Tuesday reported 24 newly confirmed COVID-19 cases, including seven locally transmitted cases and 17 arriving from outside the mainland, the National Health Commission said Wednesday.

Five of the locally transmitted cases were reported in northeast China's Liaoning Province and one each in Beijing and Heilongjiang. Beijing has reported more than 20 locally transmitted cases in the last two weeks.

Meanwhile, the city has tightened COVID-19 prevention measures for public transport to avoid overcrowding, the Beijing transport commission said Wednesday.

17 new asymptomatic cases were also reported on Tuesday, 10 of whom arrived from outside the mainland. By the end of Tuesday, a total of 4,247 imported cases had been reported on the mainland.

The total number of confirmed COVID-19 cases on the mainland reached 87,027 by Tuesday, including 356 patients still receiving treatment.