Three men were arrested after up to 60 gardaí including members of the armed and emergency response units carried out raids in Cork city on Wednesday.
The searches in the Hollyhill area are understood to have been organised after a video appeared on social media which showed men with masks carrying machetes and knives. They threatened another man over the course of the video.
Sixteen properties on a housing estate and in a halting site were raided during the operation on the northside of the city.
Firearms and ammunition, up to 50 slashooks, a bow and arrow and other weapons were seized as were two caravans, a 4x4 vehicle, and what a source described as stolen property including cash and jewellery.
The operation targeted criminals engaged in illegal activities in the city and were also linked to an investigation into a feud between two Traveller families.
The three arrested men were taken to the Togher and Bridewell Garda stations where they were detained under section 4 of the Criminal Justice Act.
It is understood the operation was not connected to an incident in Ballincollig on the southside of the city on Tuesday evening in which three men in their 20s, originally from Latvia, were injured after being set upon with slash hooks and knives. A forensic examination was carried out at the scene and the investigation continues.