Beijing on Tuesday slammed the decision by more and more countries to require COVID-19 testing from visitors arriving from China, vowing to take "countermeasures" in response.

Nations such as the US, Japan, the UK and Italy announced late last week that arrivals from China would have to present a negative test to enter their borders. More countries, including South Korea and India, have since implemented similar measures.

"Some countries have taken entry restrictions targeting only Chinese travelers," China's Foreign Ministry spokesperson Mao Ning told reporters.

"This lacks scientific basis and some practices are unacceptable," she added, warning China could "take countermeasures based on the principle of reciprocity."

Last week, Beijing had decried the new rules as "discriminatory."

Despite the threat of reciprocal measures, French Prime Minister Elisabeth Borne said on Tuesday that "we're performing our duty in asking for tests," and said that France would "continue to do it" for the foreseeable future.

Cases spike as China drops 'zero-COVID' policy

China has seen a major surge in COVID-19 infections and deaths since December. Following weeks of protests against extremely strict quarantine measures imposed by the country's "zero COVID" policy, the government of President Xi Jinping finally dropped that aim after nearly three years. The move also saw China relax entry restrictions for visitors.

Since then, other countries have complained about Beijing's lack of transparency about its COVID numbers, particularly after the government announced it would alter how it counted deaths from the virus, and that it would no longer report asymptomatic cases.

During the height of the pandemic, countries all over the world imposed quarantine, testing, and vaccine requirements on international arrivals based on the situation where the traveler was coming from.