Detectives investigating the murder of teenager Hani Abou El Kheir have arrested a further eight people, four on suspicion of murder.
Four males were arrested on suspicion of murder and one male and three females on suspicion of assisting an offender. They were being held in custody at various police stations, Scotland Yard said.
Hani, 16, was found stabbed to death on Sunday in Pimlico, central London, after an attack by a group of people believed to have been wielding knives and swords.
Police were called to Lupus Street and Hani was rushed to Kings College Hospital, where he later died.
A post-mortem examination found he died from multiple stab wounds.
The arrests on Saturday night bring the total number arrested to nine. On Thursday a 20-year-old man was arrested in north London on suspicion of murder and bailed until late March.
Police believe that at least 10 youths were involved in the incident and are keeping an open mind on the motive.
Detectives investigating Hani's murder are to return to the scene to appeal to people living in the area for help with their inquiries.