Doctor Anthony Fauci, chief medical adviser to U.S. President Biden, said Sunday that Americans who remain unvaccinated against the coronavirus are "propagating" the latest outbreak of cases of the highly contagious Delta variant.

"We have 100 million people in this country … who are eligible to be vaccinated, who are not vaccinated," Fauci said in an interview.

"We've really got to get those people to change their minds, make it easy for them, convince them, do something to get them to be vaccinated because they are the ones that are propagating this outbreak," he said.

The United States reported more than 100,000 new cases of COVID-19 on Friday, the highest daily spike since early February.