Dr. Anthony Fauci warned on Sunday that the United States is moving in the "wrong direction" as COVID-19 infections spread across the country due to unvaccinated people.

“I'm not sure it's the worst-case scenario, but it's not going to end well. When asked about a model indicating that the US may exceed 4,000 virus-related fatalities per day if vaccination rates don't increase," Fauci stated on CNN's "State of the Union."

Fauci claims that the country has the “tools” to “bend” the model's anticipated trajectory, using vaccines as an example. Vaccines have been shown to be effective against serious sickness.

“Fifty percent of the country has not been fully vaccinated. That's an issue, especially when you have a variety like Delta, which has the unique ability to transmit quickly and easily from person to person,” he explained.

“... If we don't vaccinate people, the model predicts that we'll be in trouble as we continue to see more and more cases,” he added.

The nation's top infectious disease specialist was also questioned if mask standards for vaccinated Americans would be revised.

He said, "This is under active consideration," adding that the final decision would be made by local authorities.

“If you look at what's going on locally in the trenches in places like LA County, local officials have the discretion, and the CDC agrees with that ability and discretion capability to say, ‘You know, we're in a situation where there are a lot of dynamics of infection, so even if you're vaccinated, you should wear a mask,'” he explained.

The Centers for Disease Control and Prevention reported Thursday that the seven-day average of new COVID cases in the United States was up 53% from the previous week.

Unvaccinated Americans account for 99.5 percent of COVID-19 deaths and 97 percent of hospitalizations, according to health officials.

“This is primarily a problem among the unvaccinated, which is why we're out there practically begging the unvaccinated to go out and get vaccinated,” Fauci added.