Sporadic COVID-19 cases have been reported in three cities in Henan province since Friday. On Monday, the province detected five new confirmed locally-transmitted cases and 19 asymptomatic carriers, as reported by the provincial health commission on Tuesday.

One of the five cases was from Zhengzhou, the province's capital, two were from Luoyang and two were from Xuchang. They all had been previously identified as asymptomatic cases.

Of the 19 asymptomatic carriers, one is in Zhengzhou and 18 in Xuchang, according to local health authorities.

The three cities in Henan have tightened COVID-19 prevention and control measures, implemented mass nucleic acid testing for all residents and suspended gatherings to cut off the spread.

Four subway stations in Zhengzhou have been suspended temporarily starting Tuesday, an official statement from the Zhengzhou Metro company said.

As the Spring Festival approaches, five cities in Henan — Zhengzhou, Kaifeng, Shangqiu, Zhoukou, and Xinxiang — required all returnees from outside the province to report in advance before they headed home and urged people in the cities not to leave unless necessary.