(REUTERS) - A fast-moving storm system that produced at least one tornado in Illinois threatened some 53 million people across 10 Midwestern states on Sunday, United States (US) weather officials said.
"A confirmed large and extremely dangerous tornado" was spotted near Washington, Illinois, located about 233km south-west of Chicago, the National Weather Service said, noting that the twister was moving north-east at about 88.51kmh.
It came out of a fast-moving storm system that threatened a large swath of the Midwest with dangerous winds, thunderstorms and hail, US weather officials said.
"We obviously have a very dangerous situation on our hands and it's just getting started," Ms Laura Furgione, deputy director of the National Weather Service, told reporters in a conference call.
The weather service advised that the tornado outside Peoria, Illinois, would affect mainly rural areas, with mobile homes likely to be destroyed and trees likely to be uprooted or snapped.
It was not immediately clear what, if any, damage resulted from the storm.
Tornado warnings were in effect for parts of Illinois, Kentucky, Missouri. Weather officials urged residents of areas with tornado warnings in place to take cover in interior, low-floor rooms of study buildings.