Fauci was questioned by CNN anchor Jake Tapper on whether he was part of conversations with top health officials on whether to impose a nationwide mask mandate for vaccinated Americans, and whether he thinks masks should be brought back.
Fauci said implementing mask mandates is "under active consideration," and that he is "part of the discussion," but did not say whether or not he supported mask mandates.
Fauci’s comments came amid a rise in COVID cases from the Delta variant, with Centers for Disease Control and Prevention Director Rochell Walensky claiming the variant is "spreading with incredible efficiency and now represents more than 83% of the virus circulating in the United States."
Individuals who are hospitalized with the infection are now largely those who are unvaccinated – about 99% of individuals, according to Kristen Choi, an assistant professor at UCLA School of Nursing.
Fauci added that CDC guidance still recommends that vaccinated Americans do not need to wear masks, but that local officials have the discretion to implement mandates should they choose.
"If you’re looking at what’s going on locally, in the trenches, in places like LA county, the local officials have the discretion, and the CDC agrees with that ability and discretion capability, to say ‘you know, you’re in a situation where we’re having a lot of dynamics of infection, but even if you are vaccinated, you should wear a mask," said Fauci.
He added the localities making the decision to impose mask mandates was not "incompatible with the CDC’s overall recommendations that give a lot of discretion to the locals."
Critics slammed Fauci’s comments as being about "control," and "constantly changing."
"Fauci chirping this weekend the vaccinated may well be back behind masks soon," tweeted conservative columnist Chris Stigall. "Proving this isn’t about anything other than control. It’s sure as hell not about science."
"And they wonder why the public doesn’t know who to trust when the messaging is constantly changing," tweeted Independent Women’s Voice, a conservative policy advocacy organization.
"Fauci is seriously suggesting that vaccinated people might need to wear masks again? Who is still buying this s---?" conservative comedian Tim Young tweeted.
Fauci also told Tapper that there are "two kinds of America," differentiating between the "very vulnerable unvaccinated" and the "really relatively protected vaccinated part." He also said that he wants elected leaders in "areas that are not vaccinated to get out and speak out and encourage people to get vaccinated."
In May, the CDC released guidance that people who are fully vaccinated could stop wearing masks and social distancing indoors.
Fox News' Peter Aitken contributed to this report