WASHINGTON (Reuters) - A whistleblower who says he was removed from his government post for raising concerns about coronavirus preparedness told a congressional hearing on Thursday that the United States could face “the darkest winter” of recent times if it does not improve its response to the pandemic.

Hours after President Donald Trump railed against him on Twitter, whistleblower Rick 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, a part of the U.S.