The incident happened at 8.50am as a 12 year old girl was making her way to school along BeechÂ Walk.
A man approached the girl and pushed her to the ground before threatening her with a knife andÂ leaving the scene.
The girl managed to make her way to school and raised the alarm.
Police Sergeant Richard Dickson, investigating, is keen to trace anyone who was in the Beech WalkÂ area this morning and saw the incident.
PS Dickson said: â€œThis was an unusual incident and all schools in the area have been warned andÂ extra police patrols are taking place.Â â€œThe young girl was bruised during the incident and left extremely frightened but otherwise unhurt.
Officers are now trying to trace the man who is described as having an Asian appearance, with aÂ large build and dressed in black clothes with a black bobble hat on. I would urge anyone who hasÂ seen a man matching this description in the area or anyone who saw the incident this morning toÂ contact officers as soon as possible.â€
Anyone with information relating to this crime can contact PS Dickson, in confidence, at BedfordshireÂ Police on 101, or text information to 07786 200011.
Alternatively you can contact the independent crime fighting charity Crimestoppers, anonymously, onÂ 0800 555 111.