A storm has battered St Louis, Missouri, as forecasters warned that a fast-moving weather system could threaten some 53 million people across 10 Midwestern US states.
The severe weather was also headed towards Chicago, threatening a large swath of the Midwest with dangerous winds, thunderstorms and hail, weather officials said.
The one tornado that has hit the US so far, which touched down outside Peoria, Illinois, would affect mainly rural areas, with mobile homes likely to be destroyed and trees likely to be uprooted or snapped, the weather service said.
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