New variants are emerging
"The recent rapid increase in COVID-19 transmission in China increases the potential for the emergence of new variants" of the virus, a senior U.S. health official told reporters.
Beijing has provided limited information on the variants circulating in China, according to the official, and monitoring and reports of new infections have also declined.
Italy, Japan, India and Malaysia have also announced restrictive measures to guard against the importation of variants from China.
Beijing criticized the "exaggeration, defamation and political manipulation" of the Western press about its coronavirus situation.
No death toll published
"The current development of China's epidemiological situation is predictable and under control," Foreign Ministry spokesman Wang Wenbin said Wednesday.
China still does not admit foreign visitors, and has suspended the issuance of visas for international tourists and students.
But the lifting of the mandatory quarantine sparked huge interest among Chinese people to travel abroad, after being largely confined to their own country since Beijing imposed restrictions in March 2020.
Italy argued that requiring testing of visitors arriving from that country was "essential to ensure surveillance and identification of virus variants to protect the Italian population, said Health Minister Orazio Schillaci.
In turn, French President Emmanuel Macron called for "appropriate measures to protect" his population, and assured that his government is monitoring "the evolution of the situation in China".