Fauci predicts COVID-19 cases could top 100K cases a day: 'It puts the entire country at risk'

Anthony Fauci, the nation's top infectious disease expert, told a Senate panel on Tuesday that he wouldn't be surprised if the number of new COVID-19 cases surpass 100,000 per day and warned that surges in some areas are putting the entire country at risk.

Fauci's stern warning came as local and federal health officials pleaded with the American public to wear masks, as President Donald Trump and many of his supporters willfully ignored the advice on the grounds of personal freedom.

"We can’t just focus on the areas that are having the surge. It puts the entire country at risk," Fauci told the Senate Health, Education, Labor and Pensions Committee on a hearing focused on whether schools could reopen.

"We are now having 40-plus thousand new cases a day. I would not be surprised if we go up to 100K a day if this does not turn around so I’m very concerned … I think it’s important to tell you and the American public that I’m very concerned because it could get very bad."

Fauci was responding to questions by Sen. Elizabeth Warren, D-Mass., who along with other Democrats blamed the Trump administration for not doing more to set a national standard.

"We can’t keep pretending this virus is getting better… that’s how we end up with messages like this situation in Texas racing to reopen too soon then scrambling to close down before the hospitals get completely overwhelmed," she said.

Fauci and the other top U.S. health officials warned in a joint statement that the U.S. health care system faces a "tremendous burden" this fall with the onset of the flu season and COVID-19 still circulating within communities.

Still, in a Senate hearing focused on the reopening of schools, the panel -- including Fauci -- stuck to its longtime suggestion that school openings be left up to each individual community based on how widespread the virus is there and whether local hospitals can handle an increase in sick patients.

Fauci was definitive though on one point: "Bars – really not good. Congregation in a bar inside is bad news. We’ve really got to stop that right now when you have areas that are surging like we see right now,” Fauci said.

In one sharp exchange, Paul, R-Ky., challenged Fauci and the other federal health officials on what he insisted was fearmongering by the nation's scientists when the research still presented many unknowns.

"We don’t know,” Paul said. "Why weigh in with these opinions that we have no knowledge of these are forecasts that may well be wrong. No one knows the answers to these questions. We shouldn't presume that a group of experts somehow knows what's best for everyone.”

"Virtually every day we seem to hear from you things we can’t do,” Paul said.

Fauci noted that his recommendations were based on what was known at the time. But he added that he was in "lock agreement” with Paul that researchers don’t have all the answers and said he was "completely unqualified” to say whether someone should play a sport, for example.

"I feel very strongly we need to do whatever we can to get the children back to school. So I think we are in lock agreement with that," he said.

Fauci also alluded to the pushback he got from Trump after suggesting that football might not happen this fall unless players were kept in an isolating "bubble" and tested almost every day. Trump tweeted that Fauci had "nothing to do with football.”

"I never said we can’t play a certain sport,” Fauci said Tuesday, adding that he often is asked his opinion on "certain facts about the spread of the virus."

"I give it, and then it gets interpreted that I’m saying you can’t play this sport or you can’t play that sport," he said. "I agree with you. I am completely unqualified in telling you whether you can play a particular sport or not.”

Paul responded: "Thank you. We just need more optimism.”

Later in the hearing, Fauci referenced Paul's comments to defend why he wasn't more optimistic on issues like whether the virus might die out through something called "herd immunity."

"We have to be humble and know there’s a lot we don’t know," he said of the virus.

Testifying with Fauci, director of the National Institute for Allergy and Infectious Diseases, was Robert Redfield, director of the Centers for Disease Control and Prevention; Stephen Hahn, head of the U.S. Food and Drug Administration; and Adm. Brett Giroir, an assistant secretary of Health who is coordinating testing efforts.

Sen. Lamar Alexander, the Republican chairman of the panel, said that reopening schools is important. But he also implored the American public and the president to wear masks.

In his remarks, Alexander said if Trump wore a mask, even when it wasn't necessary, others would follow his lead.

"The president has millions of admirers," said Alexander, R-Tenn. "They would follow his lead. It would help end this political debate. The stakes are too high for it to continue. Around here, senators and staff wear masks -- because we don’t want to make each other sick."

ABC News producer Sophie Tatum contributed to this story.