Shanghai has taken stringent measures to curb the spread of the COVID-19 outbreak to other provinces, said the municipal government.

The city has since April 2 mandated that people leaving the city must have a negative nucleic acid test result within 48 hours and a negative antigen test result within 24 hours, said Zhao Dandan, deputy director of the Shanghai Municipal Health Commission.

Checkpoints have been placed in airports, railway stations and highway entries to ensure all outbound passengers have valid test reports, he said.

The municipal center for disease control and prevention has been working closely with its counterparts across the country to perform epidemiological investigations related to those who have left the city.

Zhao said the city has also urged better management and protection of those who have come to aid Shanghai, such as construction workers of the makeshift hospitals and truck drivers, to ensure their safety.

The city reported 1,661 locally transmitted COVID-19 confirmed cases, 15,319 asymptomatic infections and 52 fatalities on Monday.