Police have fired tear gas at protesters in Ferguson in Missouri, as violence erupts again over the fatal shooting of an unarmed black teenager.
Officers in riot gear, supported by an armoured SWAT vehicle and a helicopter overhead, repeatedly ordered the crowd to disperse.
18-year-old Michael Brown was shot by a local policeman 10 days ago.
His death has sparked daily protests and nightly clashes with officers.
The US President Barack Obama has called for calm:
