A gang of youths wielding batons and knives terrorised and assaulted youths on a Birmingham bus as a street brawl continued on to the bus.
Three youths, aged 16 to 20, were targeted by up to 14 offenders who boarded the No 97 Travel West Midlands service to Bordesley Green.
The violence, which police are linking to an earlier assault in Stechford, broke out at about 5.30pm on Sunday as the bus arrived at a stop in Bordesley Green Road, close to an Aldi supermarket.
Last night detectives were scouring CCTV footage from cameras on the double decker bus in a bid to identify the gang members, also aged 16 to 20 and thought to be Asian.
A West Midlands Police spokesman said: "As the bus pulled into the bus stop, a dark-coloured Peugeot car reversed and parked in front of the bus and four youths got out and went on to the upper deck of the bus.
"They were then joined by around 10 other youths, who then proceeded to assault three or possibly four youths who were sitting upstairs on the bus."
Three victims were taken to hospital and later discharged after treatment for cuts and bruising.
Detective Inspector Simon Vowles, of Stechford police, said: " We are appealing for these passengers to make contact with us or anyone who was in the area at the time.
"They should contact police at Stechford on 0845 113 5000."
Phil Bateman, spokesman for Travel West Midlands, said: "Our driver radioed for help and did everything that could have been expected of him in the circumstances."