Chf Insp Chris Douglas, deputy district commander for Southampton, said officers were “swiftly in attendance” after the incident was reported.
“We know that our scenes will have disrupted people’s normal daily routines, and we want to thank local residents for their patience as we carry out our investigation,” he said.
“Thankfully, this discovery has not resulted in more serious injuries, and the boys and their families have acted quickly to report the matter to us.”
The force said patrols and house-to-house inquiries were ongoing, with residents urged to speak to officers if they had any concerns or questions.