Image by Victor Tangermann

International travelers have had to endure something humiliating when entering China via an airport: anal swab tests for COVID-19, as Reuters reports.

That's despite the fact that most other COVID tests use saliva samples taken from the mouth, nose, or back of the throat.

Visitors at a number of Chinese cities have been required to submit to additional checks, according to state media, including anal swabs — which involve a long cotton swab being inserted into the anus.

According to the country's health officials, anal swabs are better at spotting COVID infections since traces of the virus persist longer there than in the respiratory tract.

Unsurprisingly, the decision was met with outrage by the international community.

"Some Japanese reported to our embassy in China that they received anal swab tests, which caused a great psychological pain," Japan’s chief cabinet secretary, Katsunobu Kato told reporters on Tuesday, as quoted by The Guardian.

It's still unclear how many foreigners have had to undergo the test in China.

According to Reuters, South Korean visitors are able to submit stool samples instead of having their anuses swabbed.

Late last month, VICE reported that some US diplomats also received anal COVID tests. The US State Department wasn't thrilled.

"The State Department never agreed to this kind of testing and protested directly to the Ministry of Foreign Affairs when we learned that some staff were subject to it," a spokesperson told VICE.

According to the spokesperson, the tests were given "in error" and the diplomats were exempt from the test.

"We have instructed staff to decline this test if it is asked of them, as was done in the past," the spokesperson added.