THE Tactical Response Group had to be called in to deal with a teenager allegedly armed with a knife after a rooftop stand-off in Canning Vale in the early hours of this morning.

The heavily armed police team responded to reports that the teenage boy was on top of the Caltex Woolworths service station on Nicholson Road just after midnight.

Police said a negotiator was sent to the scene where they were able to convince the 15-year-old to come down from the roof.

They said that once on the ground the youth removed the knife and advanced towards police, who subdued him.

He was arrested and taken to Fiona Stanley Hospital for a health assessment.