OAKLAND -- A 13-year-old boy was in critical but stable condition after being shot in the chest Tuesday morning while walking to school in East Oakland.

The shooting happened about 9:30 a.m. in the area of 69th Avenue and Hamilton Street, a few blocks from the boy's home.

The boy, whose name was not released, told police he was walking to his middle school when he heard some shots and felt a burning in his side, which turned out to be a gunshot wound. He flagged down a passer-by who drove him to about a block away from Highland Hospital where he was dropped off. The person who drove him did not stay around to talk to authorities and the boy walked into the hospital.

Police were trying to determine if the boy was shot in a drive-by or if someone shot him on the street and whether he was the intended target. No motive has been established and no arrests have been made, police said.

Police and Crime Stoppers of Oakland are offering up to $5,000 in reward money for information leading to the arrest of the gunman. Anyone with information may call police at 510-238-3821 or a tip line at 510-773-2805.