Teenage detainees on run in NSW

Four male teenage detainees have threatened security officers with a knife before fleeing in a prison van on the NSW north coast.

At 4.30pm on Sunday police were called to North Street in Grafton where the teens allegedly threatened two security officers with a knife.

The security officers and another detainee got out of the van.

Police say four detainees, three aged 18 and one 15-year-old, then allegedly took off with the juvenile justice van.

The vehicle was found on Redgum Road shortly after.

However the detainees are still on the run.

The 18-year-olds are described as Aboriginal or Torres Strait Islander appearance, with black hair, medium builds and between 150 and 170cm tall. The fourth teen is described as being of Caucasian appearance, approximately 150cm to 155cm tall, with a thin build and brown hair.

Police have urged people not to approach the young men but to call 000 immediately.