Five teenagers are being questioned on suspicion of attempted murder after a city centre stabbing which left a 19-year-old man with critical injuries.
West Midlands Police said a 16-year-old girl and two boys aged 15 and 16 were detained during a search operation shortly after the victim was found with multiple stab wounds in Birmingham early on Saturday.
Two other youths, aged 14 and 15, were then arrested in the Rednal area later in the afternoon.
Officers were called to Belgrave Middleway at 1am on Saturday and found the victim, who has since undergone emergency surgery, collapsed on the pavement.
A police spokesman said: "Officers from across the force searched nearby canals and railway tracks supported by the force helicopter.
"A girl and a boy aged 16 were arrested nearby along with a boy aged 15. A knife was also recovered and is currently undergoing forensic examination."
Detective Inspector Ian Ingram from the force's Criminal Investigation Department said: "This was a nasty incident and our thoughts remain with the victim who is in a critical condition in hospital.
"We have spoken to a number of witnesses and we are encouraged by the progress we have made in relation to our investigation but continue to appeal for anyone with information to come forward.
"The motive for the attack remains unclear at this time but I can confirm that we are treating this as attempted murder."
Anyone with information is urged to contact West Midlands Police on 101 or the Crimestoppers service on 0800 555 111.