Biden cites new outdoor mask guidance in touting 'stunning progress' in COVID fight

President Joe Biden, speaking outdoors without a mask and touting what he called the "stunning progress" made in the fight against COVID-19, on Tuesday echoed new Centers for Disease Control and Prevention guidance that fully vaccinated Americans can now go without masks when outside in many cases.

"Starting today, if you're fully vaccinated, and you're outdoors ... and not in a big crowd, you no longer need to wear a mask," Biden said, speaking to reporters on the White House grounds on a sunny spring afternoon.

"The bottom line is clear," he said. "If you're vaccinated you can do more things, more safely, both outdoors as well as indoors."

Biden emphasized that some activities are safer than others, but said that the CDC's decision is in keeping with the science.

"The CDC is able to make this announcement because our scientists are convinced by the data that the odds of getting or giving the virus to others is very, very low," Biden said. "If you're both and fully vaccinated and out in the open air."

Biden emerged from the White House wearing a mask before taking it off to speak, but when he finished and walked away from the lectern, he kept his mask off as he headed back to the White House – a rare instance of him not wearing a mask in public.

Moments before, a reporter had asked him why he wore a mask when he first walked out given the new guidance.

Biden said he wanted the cameras and reporters to see him take his mask off outside – and keep it off.

“By watching me take it off and not put it back on until I got inside,” he said.

Biden used the new guidance as a pitch to Americans who may not have gotten the vaccine yet, saying that it is a way for Americans to be able to do more things.

"The bottom line is clear, if you're vaccinated you can do more things, more safely, both outdoors as well as indoors," Biden said. "So for those who haven't gotten their vaccination yet, especially if you’re younger, or think you don't need it, this is another great reason to go get vaccinated now."

He said that one of the perks is a feeling closer to normalcy.

"Yes, the vaccines are about saving your life, but also the of the people around you," Biden said. "But they’re also about helping to get us get back to closer to normal in our living, more normal living. Getting together with friends, going to the park for a picnic without needing to mask up."

He also discussed the success of his administration in getting shots into arms of Americans, especially in important demographics like seniors who were especially vulnerable to the pandemic.

"We’ve made stunning progress because of all of you, the American people. Cases and deaths are down, down dramatically from where they were when I took office in January 20th. And continuing to fall," Biden said. "This is particularly true for a group of Americans that we were most worried about when it came to the virus, senior citizens."

Tuesday's announcement follows Biden asking Americans in January to commit to wearing masks for his first 100 days in office, a mark he reaches on Thursday.

"Experts say that wearing masks from now just until April would save 50,000 lives, who otherwise will pass away if we don’t wear these masks," Biden said in January. "That’s why I’m asking the American people to mask up for the first 100 days."

Although it is promising news, all Americans shouldn't throw away their masks just yet. Less than one-third of Americans have been vaccinated, so the new guidance does not apply to everyone.

In addition, the pace of vaccinations being administered declined by nearly 17% in the last week, and the U.S. still averages nearly 60,000 COVID-19 cases per day.

ABC News' Ben Gittleson and Anne Flaherty contributed to this report.