An unnamed U.S. State Department official said Wednesday that Chinese officials required an unspecified number of American diplomatic personnel to submit to anal testing for Chinese coronavirus. The Chinese Foreign Ministry on Thursday denied any such testing had occurred.

The unnamed State Department official told Vice News about the alleged anal swabs Wednesday:

“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 State Department spokesperson told VICE World News on Wednesday.

The spokesperson said Beijing had assured Washington that the test was given “in error” and that diplomatic personnel were exempt from the test, which was mandatory for incoming travelers in some parts of China.

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

Reuters obtained a passive confirmation from the State Department in an email that said the department was “committed to guaranteeing the safety and security of American diplomats and their families, while preserving their dignity.”

The Washington Post reported on February 17 that some U.S. personnel stationed in China “have complained about being subjected to anal swab tests for the coronavirus by Chinese authorities, said U.S. officials.” A State Department official said all “reasonable options” were being evaluated to preserve the “dignity” of U.S. officials “consistent with the Vienna Convention on Diplomatic Relations.”

China began using anal swabs to detect the coronavirus at the beginning of this year, primarily for high-risk subjects, people who were already under quarantine, and travelers arriving in the capital of Beijing. The procedure was used more broadly during the regional coronavirus outbreaks that coincided with China’s Lunar New Year holiday. Chinese scientists claimed the anal tests were more accurate than nasal or throat testing. No other nation has incorporated this sort of testing into their regular coronavirus response at press time.

“The use of anal swabs is limited because it’s invasive and inconvenient. If a stool sample cannot be obtained, a saline-soaked cotton swab about 1-2 inches long is inserted into the anus, with the sample tested for active traces of the virus,” WebMD noted in January, highlighting the significant downside of the procedure.

Vice News recalled that an Australian traveler who was subjected to the anal test said it “felt like having diarrhea.”

The Washington Post noted that even the Chinese Communist Party’s (CCP) subjects thought the anal test was “a step too far in government intrusions after a year and counting of a dignity-eroding pandemic.” Polls showed a majority of Chinese citizens claiming they would refuse the procedure, while even Chinese doctors who believed the anal tests were highly accurate said they should only be used in special cases.

Asked about the Washington Post and Vice News reports at a press conference Thursday morning, Chinese Foreign Ministry spokesman Zhao Lijian claimed China never asked American personnel to accept the controversial testing procedure.

“I checked this with my colleagues. As far as I know, China has never asked U.S. diplomats stationed in China to do anal swab tests,” he said.