Detective Sergeant James Johnston said: “ A red BMW, with three males on board, was stopped at Queens Quay at around 5.15 pm on Thursday evening.
“A search of the vehicle was carried out and an imitation firearm discovered.
“The three men aged 28, 33 and 37 were subsequently arrested. The men remain in custody helping with enquiries.”
All three males are currently being held at Musgrave PSNI station under the Firearms (NI) Order.