Police say they responded to reports of a man with a knife in Watford this afternoon.

Several armed officers were called to Whippendell Road at 4.45pm to support local officers already at the scene.

Hertfordshire Constabulary says it was initially contacted by the ambulance service.

Watford Observer:

He was reportedly in possession of a knife.The man remains missing.

Armed officers flooded the scene and were seen at a property between Harwoods Road and Southsea Avenue.

A police helicopter was circling above and a cordon was in place in Whippendell Road.

Armed police left the scene at around 6.40pm.

Hertfordshire Constabulary has provided the following statement.

A spokesman for the force said: "At around 4.45pm today (May 13) police were contacted by the ambulance service following a report for the concern of welfare of a man in Whippendell Road, Watford.

"The man was reportedly in possession of a knife, therefore armed officers were sent to the area to support local officers.

"The road was temporarily closed as a search was conducted in an effort to try and locate the man and the police helicopter and a dog unit assisted with this.

"This appears to be an isolated incident and the man, who has yet to be found, is being treated as a vulnerable missing person. Enquiries to locate him continue.

"Anyone who has any information in relation to the incident is asked to contact Hertfordshire Constabulary via 101, quoting reference ISR 564 of May 13."