China suspended issuing short-term visas in South Korea and Japan on Tuesday, after announcing it would retaliate against countries that required negative Covid-19 tests from Chinese travellers.

China has ditched mandatory quarantines for arrivals and allowed travel to resume across its border with Hong Kong since Sunday, removing the last major restrictions under the “zero-Covid” regime which it abruptly began dismantling in early December after historic protests against the curbs.

But the virus is spreading unchecked among its 1.4 billion people and worries over the scale and impact of its outbreak have prompted Japan, South Korea, the United States and other countries to require negative Covid tests from travellers from China.

Although China imposes similar testing requirements for all arrivals, foreign ministry spokesperson Wang Wenbin told reporters on Tuesday entry curbs for Chinese travellers were “discriminatory” and China would take “reciprocal measures”.

In the first retaliatory move, the Chinese embassy in South Korea suspended issuing short-term visas for South Korean visitors. It would adjust the policy subject to the lifting of South Korea’s “discriminatory entry restrictions” against China, the embassy said on its official WeChat account.

The Chinese embassy in Japan later announced a similar move, saying that the mission and its consulates had suspended the issuing of visas from Tuesday. The embassy statement did not say when they would resume.

The move came soon after Japan toughened Covid-19 rules for travellers coming directly from China, prescribing a negative result of a PCR test taken less than 72 hours before departure, as well as a negative test on arrival in Japan.

With the virus let loose, China has stopped publishing daily infection tallies. It has been reporting five or fewer deaths a day since the policy U-turn, figures that have been disputed by the World Health Organization and are inconsistent with funeral providers reporting surging demand.

Some governments have raised concerns about Beijing’s data transparency as international experts predict at least 1 million deaths in China this year. Washington has also raised concerns about future potential mutations of the virus.

China dismisses criticism over its data as politically-motivated attempts to smear its “success” in handling the pandemic and said any future mutations are likely to be more infectious but less harmful.

“Since the outbreak, China has had an open and transparent attitude,” the foreign ministry’s Wang said.

But as infections surge across China’s vast rural hinterland, many, including elderly victims, are simply not bothering to get tested.