A 19-year-old man is in a critical condition in hospital after being stabbed in an east London street, police said.
The man was found at East Ham Underground station at about 9.30 on Sunday evening.
A second man, also aged 19, was arrested in connection with the incident after he was found with head injuries in nearby Burgess Road. He is in hospital where his condition is described as not life threatening.
Detectives believe there was an altercation in the street near the station which resulted in the two men, who are both believed to be Sri Lankan or Tamil, being injured.
Anyone with information on the incident should call Crimestoppers on 0800 555111.