According to a classified assessment prepared by American intelligence officials, China has intentionally under reported both the number of people infected by the novel coronavirus and the number of people that died from it.
Going as far as to call China's numbers "fake," the classified intelligence report also says other countries may be hiding the extent of their outbreaks.
From Bloomberg:
The officials asked not to be identified because the report is secret and declined to detail its contents. But the thrust, they said, is that China’s public reporting on cases and deaths is intentionally incomplete. Two of the officials said the report concludes that China’s numbers are fake. [...]
While China eventually imposed a strict lockdown beyond those of less autocratic nations, there has been considerable skepticism of China’s reported numbers, both outside and within the country. The Chinese government has repeatedly revised its methodology for counting cases, for weeks excluding people without symptoms entirely, and only on Tuesday added more than 1,500 asymptomatic cases to its total.
Stacks of thousands of urns outside funeral homes in Hubei province have driven public doubt in Beijing’s reporting.
If this accusation had come directly from Trump's very large mouth I would be naturally skeptical of it, but I don't have much reason to doubt the conclusions of the intelligence community. I do find it easy to believe that China's ruling party concealed the extent of the outbreak to protect their image domestically just as much if not more than internationally.
With that said, this doesn't let the Trump regime off the hook. China may have hidden their numbers and that may have even contributed to an inadequate global response, but the Trump regime also had ample time between between December and March to prepare for it. Trump did not take appropriate steps even while the virus was tearing Italy apart.
Moreover, the Washington Post recently reported that U.S. intelligence officials briefed the White House about the pandemic in both January and February so it's not as if we had no way of seeing this coming.
It is also necessarily true that our own numbers here in the United States are incorrect because we do not have enough testing capacity to assemble a complete picture. The number of publicly confirmed and reported cases, which will cross 200,000 today, does not tell us how many have actually been infected, but we can infer that many more have been.