Starting Monday, passengers in Beijing will be required to register their health code via smart phone application when taking a taxi or using a car-hailing service, according to the latest regulation announced on Sunday by the city government.

Rong Jun, spokesman of the transport commission, said at a news conference the new measure aims to further strengthen control of COVID-19 infection risks through the transportation system.

"For passengers who refuse to register, drivers have rights to refuse to provide service," he said.

The health code is a smart phone app that shows one's epidemic control-related health status with a color-codied system and can trace back one's routes.

Previously, Beijing reported three confirmed COVID-19 cases who work for a car-hailing company.

On Saturday, Beijing reported one new local confirmed COVID-19 case and one asymptomatic case. The asymptomatic case, 27-year-old male, is a driver for a car-hailing company.

Zhi Xianwei, executive deputy head of Shunyi district, where most cases were found, said on Sunday that the authority will start a second-round of mass nucleic acid testing for people living in the seven key areas near Beijing Capital International Airport in Shunyi.

"All the people in those areas should strictly follow self-quarantine before receiving the results," he said.

He also mentioned that the district will strengthen health monitoring on taxi drivers and car-hailing drivers who are required to receive testing twice a week.