Personal items, including mobile phones, were stolen from two 17-year-old boys, who also suffered facial injuries.
Police located and arrested two people near Rowlands Road in Worthing after conducting a search with the assistance of the National Police Air Service helicopter.
At this time, two 17-year-old boys arrested on suspicion of robbery remain in police custody, and our investigations are ongoing.
Anyone who witnessed what happened is asked to report it online or by calling 101 and referencing serial 1239 of 03/07.
You can also report it online or call the independent charity Crimestoppers anonymously at 0800 555 111.