WASHINGTON: The ousted director of a US agency responsible for developing drugs to fight the coronavirus pandemic filed a whistleblower's complaint on Tuesday accusing President Donald Trump's administration of retaliating when he raised concerns.

Rick Bright says in the complaint filed with a government watchdog that he warned about the virus in January and was met with hostility from Secretary of Health and Human Services Alex Azar and other high-ranking officials in the agency.

"Dr Bright acted with urgency to begin to address this pandemic but encountered resistance from HHS leadership, including Secretary Azar, who appeared intent on downplaying this catastrophic threat," reads the complaint, which his lawyers filed with the US Office of Special Counsel.

The US coronavirus death toll, now over 70,000, is the world's highest. Democratic politicians and some fellow Republicans have criticised Trump for playing down the threat of the virus and then being slow to galvanise the production of testing and protective gear.

Bright's lawyers argue that his removal as director of the Biomedical Advanced Research and Development Authority, a division of HHS, violated a federal law protecting government whistleblowers.

HHS spokeswoman Caitlin Oakley said in a statement that Bright was transferred to a job where he was entrusted to spend around $1 billion to develop diagnostic testing.

"We are deeply disappointed that he has not shown up to work on behalf of the American people and lead on this critical endeavor," Oakley said.

Bright will testify before a US House of Representatives panel on May 14, a spokeswoman for Bright said on Tuesday.

House Speaker Nancy Pelosi, the top Democrat in the US Congress, called Bright's disclosures "very damaging."

"But you know the thing is that this points to the larger issue: Where are the ethics in all of this?" she told MSNBC. "This is not a market opportunity for business, it is a moral imperative for public health in our country. The last thing we need is political interference into science."

Bright said in a statement last month that he was demoted and reassigned to another position in part because he resisted efforts to push hydroxychloroquine and the related chloroquine as cures for COVID-19, the respiratory illness caused by the coronavirus.

Bright said in the statement that the US government has promoted the medicines as a "panacea" even though they "clearly lack scientific merit."

Bright, an expert in vaccines and therapeutics, was appointed to the post in 2016 before Trump took office.

HHS said last month that Bright had been moved to a public-private partnership under the National Institutes of Health.

Trump repeatedly touted the malaria drugs as a treatment for coronavirus though few studies suggest a possible benefit.

Bright's complaint seeks his reinstatement and requests a full investigation.

In his complaint, Bright says his tensions with HHS leadership predated the coronavirus. Since 2017 he had been protesting "cronyism and award of contracts to companies with political connections to the administration," the complaint says.

The Office of Special Counsel, an independent US government agency, investigates and can prosecute abuses against federal employees.