Dr. Anthony Fauci said Wednesday that data shows hydroxychloroquine is not an effective treatment for the coronavirus, disputing use of the drug to fight the deadly virus even as President Donald Trump touts it as a potential cure and says he has taken it himself.

“The scientific data is really quite evident now about the lack of efficacy for it,” Fauci, a key medical adviser on the White House coronavirus task force, told CNN’s Jim Sciutto on “Newsroom” of the drug, adding that there’s likelihood of “adverse events with regard to cardiovascular.”

Fauci, the nation’s top infectious disease expert, is the first Trump administration official to say the drug is not effective in treating the virus based on scientific data. Medical experts and the US Food and Drug Administration, though, have questioned its efficacy and warned of potentially harmful side effects as the President has promoted the treatment.

France earlier Wednesday moved to ban doctors in the country from prescribing the drug to coronavirus patients. Asked by Sciutto if the US should similarly outlaw the drug for its patients, Fauci replied: “I’m not so sure it should be banned.”

Trump has been a frequent cheerleader for a combination of the antimalarial hydroxychloroquine and the antibiotic azithromycin as a Covid-19 treatment. He promoted the drugs nearly 50 times, despite pleas from scientists to let studies decide if the treatment worked or not. Earlier this month, the President said he was taking hydroxychloroquine to prevent coronavirus infection, although there’s no evidence it can do that.

The World Health Organization said on Monday it had temporarily halted the study of hydroxychloroquine as a potential Covid-19 treatment in its Solidarity Trial, due to safety concerns.

The WHO’s decision was made after an observational study, published last week in the medical journal The Lancet, described how seriously ill Covid-19 patients who were treated with hydroxychloroquine and chloroquine were more likely to die or develop irregular heart rhythms.

Despite the warnings from health experts, retail sales of the decades-old drug have soared in recent weeks amid the growing public attention on the medication.