Severe storms and violent tornadoes have killed at least five people and injured about 40 and flattening large parts of the city of Washington, Illinois, as they battered the US Midwest on Sunday, officials said.
The storm created tornadoes in Bone Gap and Miller City, Illinois, in Mount Carmel, Noblesville and Vincennes in Indiana, and in Paducah, Kentucky, the National Weather Service said on Sunday.
The storm system is threatening up to 53 million people across the Midwest.
The storm also forced the Chicago Bears to halt their game against the Baltimore Ravens and encourage fans at Soldier Field to seek shelter as the storm roared in.
Chicago's two major airports also briefly stopped traffic with the metropolitan area was under a tornado watch.
The city of Washington, Illinois, was hit hard by what the National Weather Service called a "large and extremely dangerous" tornado.
"It's a sad day in Washington. The devastation is just unbelievable. You just can't imagine. It looks like a war zone in our community," said Washington Mayor Gary Manier.
"It's kind of widespread and went right through our community of 15,000 people," he added, saying hundreds of homes
in the town, 233km southwest of Chicago, had been destroyed.
The state Emergency Management Agency said one person was killed in Washington.
Thirty-one people injured by the storm that hit Washington were being treated at St Francis Medical Center, one of the main hospitals in nearby Peoria, according to hospital spokeswoman Amy Paul. Eight had traumatic injuries.
Two people were killed in Washington County, Illinois, about 320km south of Peoria, said Illinois Emergency
Management Agency spokeswoman Patti Thompson.
Two people were killed in Massac County, Illinois, on the Kentucky border where a twister devastated several neighbourhoods, emergency officials said.
The agency estimated that hundreds of homes were damaged and at least 70 leveled across the state.
Stephen Wilson, a spokesman for Peoria's Proctor Hospital, said six or seven patients were being treated with minor injuries. "Mostly cuts, bruises, some broken bones," he said.
Photos from Washington, Illinois, showed buildings reduced to rubble and homes torn in half in the city of 15,000 people about 233km southwest of Chicago.
"We have reports of homes being flattened, roofs being torn off," Sara Sparkman, a spokeswoman for the health department of Tazewell County, Illinois, where Washington is located, said in a telephone interview.
Many of the injuries appeared to have been caused by collapsing structures.
The Illinois National Guard sent a 10-person fire-fighting and search-and-rescue team to Washington to help with the recovery effort.
Illinois State Police spokeswoman Monique Bond said mobile homes were toppled, roofs torn from homes, and trees uprooted.
She said officials believe some people may be trapped in their basements under debris.
The American Red Cross worked with emergency management officials to set up shelters and provide assistance to displaced residents, even as rescue workers searched for more people who might have been caught and trapped in the storm's path.
Tornado warnings were in effect for parts of Indiana and Kentucky. Weather officials urged residents of areas with tornado warnings in place to take cover in interior, low-floor rooms of study buildings.
The NWS's Storm Prediction Center said the storm moved dangerously fast, tracking eastward at 97 kilometre per hour.