U.S. Surgeon General Vice Admiral Jerome Adams delivered a somber warning to Americans on Sunday as the coronavirus outbreak speeds toward its peak, saying the crisis is about to get a whole lot worse.

“This is going to be the hardest and the saddest week of most Americans’ lives, quite frankly,” Adams said on “Fox News Sunday.”

“This is going to be our Pearl Harbor moment, our 9/11 moment. Only, it’s not going to be localized, it’s going to be happening all over the country. And I want America to understand that,” Adams said. “This is going to be a test of our resolve. It’s going to be the test of our lives. But I am confident that we can come out on the other side, based on the data and based on what I know about the American people.”

As he often does when he appears at the daily White House briefing on the coronavirus, Adams expressed a bit of optimism, too. “I want Americans to understand that as hard as this week is going to be, there is a light at the end of the tunnel if everyone does their part for the next 30 days,” he said.

Adams added that despite what occurred in China and Italy, Americans “have a power to change the trajectory of this epidemic,” noting that the aggressive actions by government officials has helped slow the spread of SARS-CoV-2.

Top officials at the daily White House briefing on Saturday said the next two weeks will be key. As of Sunday morning, the death toll stood at 8,503 people, with 312,245 testing positive, according to data kept by Johns Hopkins University Center for Systems Science and Engineering.

But the University of Washington’s Institute for Health Metrics and Evaluation (IHME) has created a forecasting model that projects future coronavirus cases and deaths in the United States overall, as well as in individual states. While many peak in the next few weeks, some states, like Virginia, will not see their peaks until mid- or late-May.

More than 40 states have issued stay-at-home orders, and Adams said recommendations coming out of Washington, D.C., are clear.

“[I]t’s why we put out these thirty days to stop the spread guidelines. These are essentially our national stay-at-home order,” Adams said. “And we’re working with governors to figure out their needs, their desires.”

Adams also said to the governors who have not yet issued stay-at-home orders that maybe they could consider a short-term directive. “If you can’t give us a month, give us a week … give us what you can.”

In a Sunday interview on CBS, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, also said “this is going to be a bad week.” But he, too, like Adams, expressed some optimism that the U.S. may soon turn the corner “within a week, maybe a little bit more.”

“So on the one hand, things are going to get bad, and we need to be prepared for that,” Fauci said. “It is going to be shocking to some. It certainly is really disturbing to see that. But that’s what’s going to happen before it turns around.”