A police officer has been shot in the arm while chasing three men, Scotland Yard has said.
The male Pc was hit by a bullet when one of the suspects opened fire on officers in Kingsdown Avenue, South Croydon, at around 10pm on Friday night.
His injuries were not life threatening and he is in a stable condition at a south London hospital.
Three men aged 22, 21 and 18 have been arrested in connection with the incident and are in custody at separate south London police stations, the Metropolitan Police said.
The two older men were arrested on suspicion of attempted murder, while the teenager detained on suspicion of causing grievous bodily harm and possession of drugs.
Scotland Yard later said the 18-year-old man had been bailed to return in early September pending further inquiries.
Officers were called to Kingsdown Avenue following reports of a group of men acting suspiciously.
A police spokesman said: "Officers attended and arrested two suspects. The third suspect ran off.
"As officers chased this man on foot he produced a handgun and shots were fired. One officer, a male Pc, sustained an arm injury."
The unnamed Pc is based with the Croydon borough Response Team. Detectives from Operation Trident, which deals with gun crime in the black community, have been informed about the incident.