A man has been arrested in connection with a shooting in an east London park.
A 27-year-old bystander was hit in the stomach when the shot was fired from outside London Fields in Hackney on Saturday afternoon.
The Metropolitan Police said there was a "disturbance between two groups of youths" following which two shots were fired.
A 19-year-old man was arrested in Hackney on Wednesday night, officers said.
The victim, who police described as a "totally innocent", remains in hospital in a serious but stable condition. His injuries are not life-threatening.
London Fields had been hosting a festival attended by hundreds of families, although the man was hit in another area of the park.
Ch Supt Steve Bending, Hackney's Borough Commander, said: "This was a callous, reckless and brazen act, without any thought by those responsible."
He added that police had been targeting gang-related violence in the borough and 125 people had been arrested for offences including firearms possession, causing grievous bodily harm, drugs supply and robbery.
Three firearms were recovered during the crackdown.
Officers from Operation Trident are investigating the latest shooting.