Police have established a secure perimeter inside a juvenile justice centre at Kariong following a disturbance, which has left seven detainees injured.
About 8.30pm (Sunday 21 July 2019), officers from Brisbane Water Police District were called to the facility following reports a number of detainees assaulted other juveniles.
An 18-year-old, who suffered stab wounds and facial injuries was transported by NSW Ambulance paramedics to Royal North Shore Hospital in a serious condition.
Another 18-year-old suffered stab wounds to his head and hands; a 20-year-old suffered facial and hand injuries; a 17-year-old had facial and head injuries; while another 20-year-old suffered injuries to his hand, leg, and arm.
Another 17-year-old dislocated his ankle after jumping off a roof.
They have all been taken to Gosford Hospital for treatment.
A seventh juvenile was later treated at the scene for a broken nose.
Additional resources have been deployed from neighbouring police districts, as well as the Public Order and Riot Squad, Operations Support Group, Dog Unit, PolAir, Traffic and Highway Patrol Command, the Rescue and Bomb Disposal Unit, and other specialist resources.
Police have established a cordon, restricting the armed detainees to a building within the complex, as negotiations continue.
Investigations into the assaults are underway, with a number of crime scenes established within the centre.
All detainees have been accounted for, and the external security of the facility was not compromised.
Anyone with information about this incident is urged to contact Crime Stoppers: 1800 333 000 or https://nsw.crimestoppers.com.au. Information is treated in strict confidence.