WASHINGTON, United States (AFP) — The United States said Tuesday that the requirement of Covid tests for travellers from China was based on science and due to Beijing’s lack of transparency on surging cases.

China earlier Tuesday denounced measures taken by a number of countries on its travellers as “unacceptable,” two days before air passengers two years and older will be required to show a negative Covid test to enter the United States.

“This is an approach that is based solely and exclusively on science,” State Department spokesman Ned Price told reporters when asked about the statement by his Chinese counterpart.

The measures have “very public health concerns that undergird them” due to “the surge of Covid-19 cases in the PRC and the lack of adequate and transparent epidemiological and viral genomic sequence data being reported from the PRC,” Price said, referring to the People’s Republic of China.

Price reiterated that the United States was ready to share its Covid-19 vaccines with China, which has heavily promoted overseas its own jabs that international health experts say are less effective.

China has seen a soaring number of Covid illnesses since it abruptly ended a policy of zero cases following rare public protests over sweeping lockdowns.