Chinese aviation authorities have said passengers who book flights to the country must prove they have recently tested negative for Covid-19 before they board.
The Civil Aviation Administration of China (CAAC) said on Monday passengers are required take the nucleic acid tests at least five days before the flight.
The tests must be carried out by institutions approved by Chinese embassies in each country, the CAAC said on its website.
It said passengers who do not provide evidence of a negative coronavirus test will not be able to board flights to China.
Commercial flights are operating to and from China, but restrictions on movement and quarantine arrangements remain for travel between different parts of the country.
China, where the coronavirus originated late last year, has largely managed to bring its epidemic under control, with localised outbreaks remaining in some regions.