WASHINGTON — In an extraordinary exchange, President Donald Trump and the government’s top infectious disease expert, Dr. Anthony Fauci, publicly sparred Friday on whether a malaria drug would work to treat people with coronavirus disease.

The scene played out on national television during the daily White House briefing on the outbreak. Anxious for answers, Americans heard conflicting ones from a just-the-facts scientist and a president who operates on gut instinct.

Reporters asked both men — first Fauci then Trump — if a malaria drug called hydroxychloroquine could be used to prevent COVID-19, the disease caused by the virus. A day earlier, when Fauci wasn’t with him at that briefing, Trump had called attention to the drug.

On Friday, Fauci took the reporter’s question and got right to the point.

“No,” he said. “The answer … is no.

“The information that you’re referring to specifically is anecdotal,” Fauci added firmly. “It was not done in a controlled clinical trial, so you really can’t make any definitive statement about it.”

He went on to explain that the Food and Drug Administration is looking for a way to make the drug available to patients for emergency use, but in a manner that gives the government data about whether it’s safe and effective. Fauci is director of the National Institute of Allergy and Infectious Diseases at NIH and in more than 30 years has handled HIV, SARS, MERS, Ebola and now the new coronavirus.

Currently, there is no medicine specifically approved for treating COVID-19.

But Trump stuck to what his gut was telling him. As the two men took turns at the podium, Trump said he disagreed with the notion that there is no magic drug for the coronavirus disease. “Maybe and maybe not, ” he said. “Maybe there is, maybe there isn’t. We have to see.”

He struck an upbeat note, while trying not to directly challenge Fauci.

“I think without seeing too much, I’m probably more of a fan of that … maybe than anybody, ” he said. “But I’m a big fan, and we’ll see what happens. And we all understand what the doctor said is 100% correct. It’s early.

“You know, I see things that are impressive … we’re going to know soon,” the president added. “And it’s very effective. It’s a strong — it’s a strong drug. So, we’ll see.”

Hydroxychloroquine and a similar drug — chloroquine — are available now and can be prescribed off-label by doctors in the United States. They may interfere with the coronavirus being able to enter cells, and some scientists have reported possible encouraging signs in test-tube and other small studies.

Other scientists are skeptical that those promising test-tube results will translate to benefits for patients.

On Friday at the White House podium, Fauci’s caution did little to dampen Trump’s enthusiasm.

“Look, it may work and it may not work and I agree with the doctor,“ Trump said. “It may work, it may not work. I feel good about it. That’s all it is. Just a feeling. You know, I’m a smart guy. I feel good about it. And we’re going to see. You’re going to see soon enough.”

The two even debated the safety of the malaria drug, with Trump saying it has a proven record and Fauci cautioning that safety has to be validated again because it would be used to treat the coronavirus disease, which is different.

In the end, the scientist seemed to be trying to find a way to avoid a direct confrontation with the president.

“No, there really isn’t that much of a difference in many respects with what we’re saying,” Fauci tried to explain. “The president feels optimistic about something. His feeling about it. What I’m saying is that it might — it might be effective.”