Police are warning of the dangers of terror-related pranks after a replica suicide vest was found just days after the Paris attacks.
The item was hung on railings in Sheffield city centre in the week following the attacks on the French capital, which left 130 people dead.
South Yorkshire Police said that the item could have caused mass panic, considering it was so close to the terrorist attacks across the Channel.
Detective Chief Inspector Steve Whittaker said: "While the item was quickly determined to be a hoax, given the recent events in Paris, this clearly had the potential to cause widespread distress and draw a significant policing response.
"Following investigation, I believe this incident was an ill-judged prank, but people must remember the very real dangers of this type of behaviour.
"If someone had been seen with the vest the policing response would have, in all probability, involved armed officers and placed the individual in very serious danger.
"Recent events in Paris have brought into sharp focus the type and scale of threat posed by international terrorism, and the relationship between the police and the public needs to be stronger than ever before to counter this threat."
Police were called at 12.11pm on Thursday, November 19 by a member of the public after seeing the item hung on railings in central Sheffield.
Officers attended the scene on Furnival Gate and it was discovered that the item was a homemade replica which contained no viable parts or explosive elements.
DCI Whittaker added: "The member of the public did exactly the right thing in contacting police immediately, but it's vitally important that policing resources are used to deal with real threats and not foolish pranks."
Police are investigating who left the item and are asking anyone with information to come forward.
Officers said that it is important for the public to remain vigilant and to report anything that could be terrorist-related to specialist officers via the confidential Anti-Terrorist Hotline on 0800 789 321.