GLEN ALLEN, Mo. — A large tornado tore through southeastern Missouri before dawn on Wednesday, killing at least five people and causing widespread destruction as a broad swath of the Midwest and South kept a wary eye out for further storms that could spawn additional twisters and hail.

The tornado touched down around 3:30 a.m. and moved through a rural area of Bollinger County, about 50 miles (80 kilometers) south of St. Louis, said Sgt. Clark Parrott of the Missouri State Highway Patrol.

Trees were uprooted and homes turned into piles of splinters. One building was flipped on its side. Drone footage showed emergency crews peering into the wreckage with flashlights.

More than 20 agencies were part of the search for survivors and victims, with the damage so bad that they sometimes were forced to use chainsaws to cut back trees and brush to reach homes, Parrott said.

“The damage is pretty widespread. It’s just heartbreaking to see it,” Parrott said.

The twister caused significant destruction in and around the small rural communities of Glen Allen and Grassy, Bollinger County Sheriff Casey A. Graham said in a Facebook post. A hunting area separates the two communities.

At least five people were killed, Graham wrote, noting that he was withholding the names of the dead to make sure their families could be notified first.

“Please understand the scope of this operation," he said. "I know everyone wants updates and news of what happened. As your Sheriff, I am focused on ensuring those who still need help are receiving it, and we account for all our citizens.”

Charles Collier, 61, said he saw the coroner’s van drive by with its lights on in Glen Allen, where he owns a storage facility.

“That was a sad, sad sight -- knowing there was bodies in there,” said Collier, who wasn’t entirely relieved when he saw his facility was spared. “I was just numb, thinking about all these other people, what they’re going through."

Josh Wells said that the tornado tore half of the roof off his Glen Allen home and pushed in his bedroom wall. Luckily, he fled beforehand with his son to his sister’s home because it has a basement.

“We all ran down and huddled against the wall and my brother-in-law made it down just seconds before we heard the roaring sound of the wind and debris crashing around us,” he said.

While his sister’s home held up, the area reeked of gas because a propane unit was damaged.

Justin Gibbs, a National Weather Service meteorologist in Paducah, Kentucky, said the tornado remained on the ground for roughly 15 minutes, traveling an estimated 15-20 miles (24-32 kilometers).

A weather service team was headed to Bollinger County to gather details about the tornado, but Gibbs said it’s clear “it was big. It was a significant tornado.”

He noted that tornadoes are especially dangerous when they touch down late at night or early in the morning, as this one did.

“It’s definitely a nightmare from a warning standpoint,” Gibbs said. “It’s bad anytime, but it’s especially bad at 3:30 in the morning.”

Larry Welker, Bollinger County's public administrator, said the twister traveled along route 34 into Glen Allen, a village of slightly more than 100 people, and that he hasn't been able to inspect the damage firsthand because law enforcement were restricting access to the area.

“I’m getting reports that it was pretty bad,” he said. He described it as a rural area, where residents mostly farmed, cut timber or worked construction jobs.

“There was several trailers there, and I understand that there is still people missing,” Welker said.

Gov. Mike Parson said he would join emergency personnel on the ground to assess damage and determine what resources are needed. They planned a news conference in the afternoon.

Missouri's U.S. Sens. Eric Schmitt and Josh Hawley, meanwhile, said they’re in touch with local leaders and ready to help. Schmitt also warned Missouri residents in a statement to stay alert “as there’s more severe weather on the horizon.”

The storms moving through the Midwest and South on Wednesday threaten some areas still reeling from a deadly bout of bad weather last weekend. The Storm Prediction Center said up to 40 million people in an area that includes major cities including Chicago, Indianapolis, Detroit and Memphis, Tennessee, were at risk from the storms later Wednesday. As of late morning, the the greatest threat appeared to be to an area stretching from lower Michigan into Tennessee and Kentucky.

Fierce storms that started last Friday and continued through the weekend spawned deadly tornadoes in 11 states as the system plodded through Arkansas and into the South, Midwest and Northeast.

Schools in Little Rock, Arkansas, canceled Wednesday classes because the storms were expected to move through the area during the morning rush, KFVS-TV reported.

In central Illinois, authorities said five people were hurt and about 300 homes were without power due to a tornado that struck in Fulton County on Tuesday evening. Chris Helle, who directs the county’s Emergency Services Disaster Agency, said one of the people injured was in critical condition.

Helle said the damage was concentrated near the town of Bryant, about 200 mile (322 kilometers) southwest of Chicago. Fire departments and other first responders were still cataloguing the damage there, but Helle said numerous homes had been destroyed. He credited people for listening to advance warnings and taking shelter.

Officials said another tornado touched down Tuesday morning in the western Illinois community of Colona. Local news reports showed wind damage to some businesses there.

Winds of up to 90 mph (145 kph) and baseball-sized hail also caused damage in the Quad Cities area of Iowa and Illinois.

The National Weather Service also received reports of semitrailers that had been tipped over by winds in Lee County, about 95 miles (153 km) west of Chicago.