CNBC reports that the battle against the coronavirus pandemic is like "the fog of war," said renowned top American health official Anthony Fauci in an interview with Science magazine, adding that it was "premature" to assess whether the U.S. plan has failed or not.

In answer to what went wrong in the U.S. and "why did this fail" despite the country's pandemic preparedness, Fauci said: "I think we'll have to wait until it is over and we look back before we can answer that."

Fauci, who has been on the frontline of the government response to the COVID-19 outbreak, flagged that testing is one "clear" issue that needs to be looked at again.

Testing for the coronavirus across the U.S. has been criticized as unacceptably inadequate and slow. That's prevented health officials from understanding the full scope of the outbreak, American hospital leaders told CNBC earlier in March.

"Why were we not able to mobilize on a broader scale? But I don't think we can do that right now. I think it's premature. We really need to look forward," Fauci said in the interview with Science.