Russian security services have released images showing what they claim is the US diplomat Ryan Fogle being detained in Moscow, and objects found in his possession.
Security services said Fogle had been handed over to US Embassy officials.
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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.