China has described the extension of international restrictions on travellers from its territory as "unacceptable" as countries including France, Japan, India and the United States impose Covid controls on visitors from the world's most populous nation.
More than a dozen countries are now insisting that all travellers from China provide negative Covid tests before arrival, as concerns grow over a surge in cases.
China's steep rise in infections comes after Beijing abruptly lifted hardline restrictions last month, with hospitals and crematoriums quickly overwhelmed.
Despite that upsurge in the number of cases, Beijing has pushed ahead with the re-opening, announcing an end to mandatory quarantine on arrival in a move that prompted many Chinese to plan trips abroad.
"Some countries have taken entry restrictions targeting only Chinese travellers," foreign ministry spokesperson Mao Ning told a regular briefing.
"This lacks scientific basis and some practices are unacceptable," she added, warning that China could take countermeasures.
Borne defends French demands
French Prime Minister Elisabeth Borne has defended the new rules.
"I think we're performing our duty to protect French people in asking for tests," Borne told a radio news channel.
Read more on RFI English
France, Britain impose Covid tests on travellers from China
EU chief Charles Michel heads to China amid Covid protests crackdown
French health chiefs call for at risk citizens to get second Covid booster jab