Hong Kong police have fired pepper spray at protestors angry about an extradition bill that would allow people to be sent to mainland China for trial. Tens of thousands of demonstrators, most of them young people dressed in black, had gathered peacefully outside government buildings in the Chinese-ruled city before tempers flared, with claims some threw bottles at officers. Rubber bullets were also used to try and keep people back as the protests turned to chaos, with some campaigners charging officers with umbrellas. Ambulances were seen heading towards the crowds as a police chief warned protestors they ‘must stop the violence’, and urged residents to stay away from the area. The demonstrations forced the delay of a legislative debate over the controversial bill.