A Chinese foreign ministry spokesperson said Friday the United States is the biggest saboteur of the World Health Organization's (WHO) ability to perform its functions independently and without interference.

Spokesperson Zhao Lijian made the remarks at a daily press briefing in response to U.S. attacks against China on the issue of COVID-19 origin tracing.

Calling U.S. attacks a farce of a thief shouting "stop the thief," Zhao said it is the United States that has blatantly withdrawn from the WHO and threatened to stop paying its dues, and it is also the United States that is openly stigmatizing the epidemic, labeling the virus, and interfering with WHO's global response.

While China is actively implementing the recommendations of the first-phase joint mission report and conducting follow-up complementary studies, the U.S. side is engaged in politically-motivated origin-tracing in defiance of authoritative scientific research conclusions, spreading false information and lies, and flagrantly distorting the position of other countries, Zhao said.

Noting the "political virus" also needs to be traced as does the coronavirus, the spokesperson urged the United States to respect science, stop sabotaging international cooperation on fighting the epidemic and tracing the source of the virus, and adopt an open, transparent and cooperative attitude to invite WHO experts to the United States for origin-tracing study.

"Smearing other countries cannot help whitewash the United States itself," Zhao said, urging the U.S. side to address doubts concerning its bio-labs and early cases, among others.

In response to U.S. media reports that health authorities of Florida have deleted data about the 171 patients with COVID-19 symptoms or tested positive for coronavirus in January and February of 2020, Zhao said the U.S. move once again revealed the political plot of the United States to cover up the epidemic.

"These U.S. politicians owe the world a responsible explanation for what they have done in callous disregard for facts, science and human life," Zhao added.