Donald Trump has lashed out at Dr Deborah Birx, the White House Coronavirus Response Coordinator, for the first time, calling her response to criticism "pathetic" after she admitted that the coronavirus was widespread throughout the US.
The president said House Speaker Nancy Pelosi had criticised Dr Birx because she was "too positive" about the US coronavirus response.
"So Crazy Nancy Pelosi said horrible things about Dr Deborah Birx, going after her because she was too positive on the very good job we are doing on combatting the China Virus, including Vaccines & Therapeutics," Mr Trump tweeted. "In order to counter Nancy, Deborah took the bait & hit us. Pathetic!"
The "horrible things" Mr Trump is referencing are comments Ms Pelosi allegedly made to White House Treasury Secretary Steve Mnuchin and White House Chief of Staff Mark Meadows during a meeting last week.
"Deborah Birx is the worst. Wow, what horrible hands you're in," Ms Pelosi is reported to have said, according to a report from Politico.
She had publicly criticised Dr Birx before, though in more diplomatic terms. She said that because Dr Birx was a Trump appointee, she did not have confidence in the doctor.
"I think the president has been spreading disinformation about the virus and she is his appointee, so I don't have confidence there, no," she said during an interview with ABC News.
Dr Birx first entered White House service when she was nominated by Barack Obama to act as an Ambassador at Large and as a US Global AIDs Coordinator in 2014.
On Sunday, Dr Birx appeared on CNN and was asked for her response to Ms Pelosi's comments.
The doctor said she had "tremendous respect for the Speaker" and that all of the guidance she provides the Trump administration is based on data.
She then went on to say that the US had entered a "new phase" in its battle against the coronavirus, which she said was "extraordinarily widespread".
"What we are seeing today is different from March and April. It is extraordinarily widespread ... it's more widespread and it's both rural and urban," Dr Birx said. "To everybody who lives in a rural area, you are not immune or protected from this virus.
"And that is why we keep saying, no matter where you live in America, you need to wear a mask and socially distance, do the personal hygiene pieces."
Mr Trump's criticism of Dr Brix marks the first time he's publicly attacked the doctor. The president has made a habit out of undermining and attacking other doctors working for the White House.
Dr Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases and one of the White House's top doctors responding to the virus, has frequently been targeted by the president.