Whistleblower warns of 'darkest winter' if U.S. doesn't plan against virus

Hours after President Donald Trump railed against him on Twitter, Bright testified to a U.S. House of Representatives panel about readiness for the outbreak.

Bright was removed last month as director of the Biomedical Advanced Research and Development Authority, or BARDA, which is responsible for developing drugs to fight the coronavirus.

"What we do must be done carefully with guidance from the best scientific minds. Our window of opportunity is closing. If we fail to improve our response now, based on science, I fear the pandemic will get worse and be prolonged," Bright said.

Trump, who has been pushing for the U.S. economy to reopen quickly, dismissed Bright as a "disgruntled employee" on Twitter on Thursday morning before the hearing begun.