The warning from top US health experts came during a hearing about the latest efforts by the US government to contain the pandemic as several states struggle to contain the virus amid growing cases and state reopens. The United States reported more than 40,000 new cases of Covid-19 on Friday, its biggest daily jump to date.
Redfield singled out younger Americans in particular to convey a message that they are not exempt from the need to wear a mask.
"It is essential that we all take personal responsibility for delaying the transmission of Covid-19 and adopting the universal use of face covers," he said. "Specifically, I am targeting the youngest members of our society, Millennials and Generation Zs. I ask those who are listening to spread the word."
Fauci spoke of the general importance of wearing masks.
"We are all in this together," he said, adding: "We recommend masks for everyone on the outside, anyone who comes into contact in a crowded area. You should avoid crowds when possible and when you are outside and have no ability to keep your distance, you must wear a mask at all times. "
Fauci indicated that he would support an effort to increase the production of high-quality masks in the United States and distribute them free of charge to the American public in response to a question by Vermont Independent Senator Bernie Sanders.
"Masks are extremely important," Fauci said, adding: "There is no question that wearing masks protects and protects you. So people protect each other. Anything that encourages the use of masks, whether it be giving away masks or any other mechanism, I am completely in favor of ".
Republicans have focused on the last week of July to reach an agreement on the next round of stimulus legislation. Senate Majority Leader Mitch McConnell has been steadfast on that schedule for weeks and the administration is on board.
This story has been updated with additional developments on Tuesday.
CNN's Amanda Watts, Alison Main, Phil Mattingly and Katie Lobosco contributed to this report.