President Trump on Thursday criticized health official Rick Bright and said he should “no longer” be working for the federal government shortly before the whistleblower was slated to testify before a House panel about the Trump administration’s response to the novel coronavirus.

Trump tweeted that he had never met nor heard of Bright and claimed that the former federal vaccine doctor was "not liked or respected" by people whom the president has consulted, labeling him a “disgruntled employee.”

“I don’t know the so-called Whistleblower Rick Bright, never met him or even heard of him, but to me he is a disgruntled employee, not liked or respected by people I spoke to and who, with his attitude, should no longer be working for our government!” Trump tweeted Thursday morning.

Bright delivered critical testimony to a House committee later Thursday about the Trump administration’s response to the coronavirus pandemic. He warned that without a national coordinated response this year will could be “the darkest winter in modern history.” 

“Without better planning, 2020 could be the darkest winter in modern history,” Bright told the House committee. “First and foremost, we need to be truthful with the American people. American deserve the truth. The truth must be based on science. We have the world's greatest scientists. Let us lead. Let us speak without fear of retribution.”

Bright served at the helm of the Biomedical Advanced Research and Development Authority from 2016 until last month, when he was reassigned to a narrower position based at the National Institutes of Health.

Bright filed a whistleblower complaint following his reassignment alleging that his early warnings about the virus were met with indifference at the Department of Health and Human Services and that his efforts to push back on the use of hydroxychloroquine to treat the coronavirus, something Trump touted, contributed to his removal from the high-level post.

Bright is seeking to be reinstated in his former position and asked for a full investigation into the decision to reassign him.

Bright, who first came forward with his claims in late April, testified before the House Energy and Commerce Subcommittee on Health beginning at 10 a.m. Thursday morning.

HHS strongly pushed back on Bright’s allegations in a statement issued during the hearing and accused him of an effort to politicize the federal response to the coronavirus.

“Rick Bright was transferred from his role as BARDA director to lead a bold new $1 billion testing program at NIH, critical to saving lives and reopening America. Mr. Bright has not yet shown up for work, but continues to collect his $285,010 salary, while using his taxpayer-funded medical leave to work with partisan attorneys who are politicizing the response to COVID-19,” HHS said.

“His whistleblower complaint is filled with one-sided arguments and misinformation. HHS is reviewing the complaint and strongly disagrees with the allegations and characterizations made by Rick Bright,” the department said.

Trump has repeatedly said he didn’t know Bright, while dismissing him as a seemingly “disgruntled employee."

“I don’t know who he is. I did not hear good things about him at all,” Trump told reporters at the White House on May 6. “And to me he seems like a disgruntled employee that’s trying to help the Democrats win an election.”