WASHINGTON (AP) — Surgeon General Jerome Adams offered some of the starkest warnings yet Sunday as he braced Americans for the worsening fallout from the new coronavirus, warning “this is going to be the hardest and the saddest week of most Americans’ lives, quite frankly.”

The number of people infected in the U.S. has exceeded 300,000, with the death toll climbing past 8,400; more than 3,500 of those deaths are in the state of New York. 

Much of the country is under orders to stay home, and federal officials said that have seen signs that people are listening to the message about social distancing. But the Trump administration is also emphasizing that the worst is yet to come for many communities.

“This is going to be our Pearl Harbor moment, our 9/11 moment, only it’s not going to be localized,” Adams said on “Fox News Sunday.” He added: “It’s going to be happening all over the country. And I want America to understand that.”

For most people, the virus causes mild or moderate symptoms, such as fever and cough that clear up in two to three weeks. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia, and death.

A few states have declined to order residents to stay home. Adams was asked on NBC’s “Meet the Press” if they should join the rest of the country.

“Ninety percent of Americans are doing their part, even in the states where they haven’t had a shelter in place,” Adams said. “But if you can’t give us 30 days, governors, give us, give us a week, give us what you can, so that we don’t overwhelm our health care systems over this next week.”