Flash flooding that left at least three dead and one missing in Colorado worsened as torrential rain continued to pound the state.
Thousands have been forced to flee to higher ground as rising water toppled buildings, stranded motorists, cut off remote towns and forced the state's largest university to close.
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The Democratic presidential candidate may also have shown his cards on his choice of running mate.
The US president also shared a post on Twitter accusing Dr Anthony Fauci of misleading the public over hydroxychloroquine.
Fears over an impending second wave of coronavirus dominates Wednesday’s front pages.