An investigation is underway after gardaí (Irish police) were threatened with what is believed to be a "realistic imitation firearm" in Dublin on Saturday.
Gardaí had been attempting to arrest a man when a struggle broke out which also resulted in a garda being assaulted.
Commissioner Justin Kelly said the incident "demonstrates once again the potential dangers that our members face every day".
An Garda Síochána (Irish police) said searches are ongoing for the gun, adding they are appealing to anyone who witnessed the incident to come forward.
Gardaí had been on active patrol on Abbey Street in Dublin city centre shortly before 05:00 local time.
The man, who had been riding a bike, was pursued by two uniformed Gardaí and a trainee Garda.
The man had thrown the firearm into the River Liffey as he fled from the scene.
Police said a magazine from the weapon was recovered and sent for forensic examination adding "preliminary examination of the magazine would indicate the weapon is a "realistic imitation firearm".
