Researchers in Hong Kong estimate that the actual number of coronavirus cases in China could be as much as four times higher than officials have said publicly.

Their study, published Tuesday in health journal The Lancet, blamed the purported undercount on the evolving definition of what China's top health commission considered a confirmed case.

"From Jan 15 to March 3, 2020, seven versions of the case definition for COVID-19 were issued by the National Health Commission in China. We estimated that when the case definitions were changed, the proportion of infections being detected as cases increased," reads the study's abstract.

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"The changes in case definitions had a clear effect on the proportion of infections that were identified and counted as confirmed cases," researchers continued. "Before Jan 23, we estimated that 92% ... of cases were undetected."

The actual number of coronavirus cases within China, researchers concluded, could be as high as 250,000. The study's data was compiled using results gathered by the World Health Organization's mission to Wuhan, China, where the virus is thought to have originated.

Chinese officials have faced criticism from Washington over alleged inaccuracies in Beijing's official coronavirus case count, as well as allegations of U.S. involvement in the virus's spread.

In recent days, China was sued by the state of Missouri over officials' handling of the outbreak, a move officials in Beijing called "absurd."