The ousted director of a key U.S. agency charged with developing drugs to fight the COVID-19 pandemic said Wednesday he was dismissed because he called for careful vetting of a treatment frequently touted by President Donald Trump.

Rick Bright said in a statement that he was replaced as director of the Biomedical Advanced Research and Development Authority, or BARDA, and reassigned to a new role because he resisted efforts to push hydroxychloroquine and the related chloroquine as cures for COVID-19, the respiratory illness caused by the new coronavirus.

"While I am prepared to look at all options and to think 'outside the box' for effective treatments, I rightly resisted efforts to provide an unproven drug on demand to the American public," Bright said in the statement, reported by multiple U.S. media outlets Wednesday.