( CNN ) -- Police have released dramatic security camera footage they say shows masked and hooded rioters firing shots at unarmed officers and a police helicopter in the English city of Birmingham . They hope the public will come forward with information as they investigate the violence that took place amid widespread rioting earlier this month . The footage shows a group of 30 to 40 young men , dressed in black , in the Newtown area of Birmingham as they attacked a pub late on Tuesday August 9 , West Midlands Police said in a statement . As police tried to disperse the group , petrol bombs were thrown at a police car and shots were fired , police said . Officers believe the rioters intended to set fire to the pub . Chief Constable Chris Sims said the incident was being treated as attempted murder and arson . The force has taken the `` unusual step '' of releasing the footage because of the potential for serious harm to his officers and members of the public , he said . `` Eleven shots were fired at unarmed officers to enable disorder to continue , whilst petrol bombs were also thrown at officers who initially attended the scene , '' he said . `` This footage shows seemingly co-ordinated criminal behaviour with no regard for people 's lives , whether it be through the setting of a fire , shooting at unarmed officers or shooting at the police helicopter . '' West Midlands Police have so far arrested more than 500 people over the disturbances in Birmingham and nearby towns , of whom more than 140 have been charged . On Friday , Prince William and Catherine , the Duchess of Cambridge , visited areas of Birmingham affected by the disorder . They met with residents including a small business owner whose store in central Birmingham was looted , local community leaders and emergency responders . Among the places they visited was Winson Green , an inner-city area where three young Asian men were killed by a hit-and-run driver amid the disturbances . Four men have been charged over their deaths and police continue to question other suspects . An eighth man was arrested Friday on suspicion of murder , police said . Funeral for men killed in UK riot .
NEW : Prince William and Catherine visited Birmingham to meet people affected by the riots . Police say 11 shots were fired at officers and a force helicopter . Police hope members of the public will help them identify those involved . The violence came amid widespread disturbances in English cities this month .