Sources say at least two people are under arrest in connection to the shooting death of a 4-year-old Bronx boy.

One of those in custody is 17 years old, according to sources.

Police Commissioner Ray Kelly said a 17-year-old teen admitted to firing a gun in Morrisania Sunday night but it's not clear if he's the one who fired the fatal shot.

Kelly said the teen claims he was shooting in self-defense and that police are still looking for other suspects.

"We're speculating that there was at least three, possibly four," he said. "There were three different types of ammunition found but there may have been more than three weapons involved."

"Nothing is going to bring back the life of the four-year-old," Mayor Michael Bloomberg said. "What we've got to do is make sure we don't take more lives."

4-year-old Lloyd Morgan was shot and killed on the playground.

It's unclear what the charges are against the two individuals in custody.