London: A murder inquiry was under way yesterday after a 13-year-old boy injured in a fight near West Ham's football ground died in hospital.

The boy was left with a severe head injury in the clash between rival school gangs near the Upton Park ground in Newham. Five youths arrested in connection with the fight were yesterday still in custody at east London police stations.

The Lithuanian teenager suffered serious brain injuries in a battle between rival groups of boys from two schools in West Ham. Police are appealing for witnesses to the fight, which was in Princes Terrace on Wednesday afternoon.

Witnesses told how the boy, a pupil at Brampton Manor Comprehensive, was cornered by a gang of up to 20 youths from Lister Community School. One said: "A gang from Brampton Manor came down to Lister School looking for a fight. Some of them were carrying weapons.

"I didn't see what kind, but they looked like bars or poles. I didn't see any knives. There is quite a big rivalry between the two schools.

"Loads of kids from Lister Community School they looked between 13 and 16 years old came out to meet them. There must have been 30 or 40."

Detective Chief Inspector Jason Gwilliam, of the Serious Crime Directorate, said officers were working closely with the schools.

Police believe the fight may have been sparked by an minor argument between members of the two groups earlier in the week. Officers responding to calls about a disturbance found the boy lying in the street.