Five boys from Gloucester have been arrested on suspicion of a firearms offence following an incident involving a BB gun in the city centre.
Police said officers were called to a report of a group of males brandishing a knife on Eastgate Street at about 2215 GMT on Wednesday.
After CCTV was checked, officers believed it to be a firearm.
Armed police went to the scene and challenged the group before the BB gun was seized.
Three 15-year-old boys, a 16 year old and a 17 year old were arrested and have been bailed to attend Gloucester Police Station on 12 June.
Ch Insp Rich Burge said: "We took this report extremely seriously as the public would expect and sent trained firearms officers to the scene to protect the public and apprehend those responsible.
"To find out that this was youngsters with a BB gun was astounding.
"Waving any gun or weapon around is a completely foolish act that not only causes mass panic and fear but also costs us, as a force, considerable resources that may be needed elsewhere."