The incident occurred at around 2pm on Wednesday (4/4) between the shops on Ardwell Lane, Greenleys and Wolverton.
Three men were involved in a fight outside the shops in Greenleys. One of these men was then chased by the other two men in the direction of Wolverton.
The two men then approached a group of 13-year-old boys on the pathway that leads past Greenleys Junior School. The men threatened to assault the boys in order to steal their bikes
They pushed two of the boys off their bikes and rode away on them.
The two offenders caught up with the third man and a second altercation took place where a machete was used.
The first offender is described as a black man in his late teens to early twenties. He was wearing a green parka jacket with a hood.
The second offender is described as a white man in his late teens to early twenties. He was wearing a grey top and dark bottoms. It is believed he sustained a facial injury from a knife during the altercation.
Investigating Officer, Detective Constable Chris Bigg, based at Milton Keynes Police Station said: “We would like to hear from anyone who witnessed the incident or has any information about the offenders to contact us.
“We are currently conducting door to door enquiries and reviewing CCTV. If there are any residents that have captured the incident on CCTV, we would like to hear from you.
“Please call the Thames Valley Police non-emergency number on 101, quoting reference 43180100547, or alternatively Crimestoppers anonymously.”