President Barack Obama has appealed for calm on the streets of Missouri after days of clashes between police and protesters.
The tensions follow the fatal shooting of a black teenager by a police officer in the St. Louis suburb of Ferguson.
President Obama said there was "no excuse" for "police to use excessive force against peaceful protesters" or for "violence against police".
ITV News' Washington Correspondent Robert Moore reports:
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A rollercoaster has reportedly come off the rails at a theme park in Scotland.
"I saw a lot of smoke come out from the tail-end of the aircraft. I wondered if it was normal, whether it was just exhaust fumes."
The House of Commons Petitions Committee has said they will keep an eye on the petition and are concerned about fraudulent signatures.