Illinois Gov. JB Pritzker announced Wednesday that all pre-K through 12th grade schools and day cares must follow universal masking indoors regardless of vaccination status.

Pritzker said the state is facing a growing threat from the delta variant and noted that children under 12 aren't yet eligible for COVID-19 vaccines.

"Far too few school districts have chosen to follow the federal Centers for Disease Control and Prevention prescription for keeping students and staff safe," he said at a news conference. "Given the CDC’s strong recommendation, I had hoped that a state mask requirement in schools wouldn’t be necessary, but it is."

The latest delta surge is once again pushing hospital staffing to breaking points across the U.S.

In Alaska, Idaho, Oregon and Washington, some "facilities are experiencing substantial shortages of both clinical and support staff," according to a Department of Health and Human Services planning document obtained by ABC News Wednesday.

In hard-hit Missouri, many hospitals "don’t have the staff to support a surge without further modification to operational strategies," the document said.

At a Shreveport, Louisiana, hospital, where the number of COVID-19 patients are multiplying, nurse Melinda Hunt told ABC News, "To be honest, I probably cry most days at work. And I cry at home. I’m tired. I’ve been doing this a year and half. It feels like it’s never going to end."

The U.S. daily case average has climbed to more than 84,000, a 45.3% jump in the last week, according to federal data.

The daily case average is now more than seven times higher than it was six weeks ago.

All but three states are now reporting high (a seven-day new case rate ≥100) or substantial (a seven-day new case rate between 50-99.99) community transmission, according to federal data.

-ABC News’ Arielle Mitropoulos

The delta variant now accounts for 93% of all sequenced cases in the U.S., according to the latest CDC data, which was collected over the last two weeks of July.

Delta accounted for just 3% of cases sequenced in late May.

Across the Midwest, described as HHS regions 7 and 8, delta made up 97% to 98% of cases. This includes Iowa, Kansas, Missouri, Nebraska, Colorado, Montana, North Dakota, South Dakota, Utah and Wyoming.

-ABC News’ Cheyenne Haslett

Tom Bossert, a former White House homeland security adviser and an ABC News contributor, painted a somber picture of the COVID-19 crisis unfolding, saying, "It's too late for any meaningful mitigation" in Gulf states.

Bossert warned that hospital systems in hard-hit states could be overwhelmed within a few days as the delta variant spreads further.

"If this pace continues for the next four or five days, which it seems it will, the hospital systems in Florida and Louisiana will collapse. That's how bad this is. By 'collapse,' I mean they will be full, their ICUs and their hospitals, they will be turning away patients," he said on "Good Morning America" Saturday.

"In some states -- Florida, Louisiana, Texas is looking bad -- all through the Gulf Coast, I believe it's too late for any meaningful mitigation," he continued. "In other words, there is so much disease that what we're seeing is a mathematical certainty."

Bossert urged federal and local governments to focus on providing aid to overburdened hospital systems.