Fans are receiving medical treatment after at least ten cars crashed into each other during the Daytona Speedway, causing debris to fly into the stands.
Reports differ on the number of spectators injured as a result of the accident which took place before NASCAR's main event the Daytona 500.
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The operation to recover the unexploded bomb near the Houses of Parliament let to disruption in central London overnight.
Southern parts of England and Wales will see sunny skies after a frosty start.
A police spokesman said the incident in the Bourke Street Mall on Friday was not related to terrorism.