Gardaí in Dundalk have arrested 13 men and women as part of a year-long investigation into the sale and supply of heroin.
Officers - with the help of the Drugs and Organised Crime Bureau - say they targeted 30 people, and expect to have the majority of them before court by next Wednesday.
Superintendent Gerry Curley says communities have suffered as a result.
He said: "We've had a number of isolated incidents where firearms have been used, where shots have been fired at houses, where pipe bombs have been left at houses.
"And that's a serious danger to the people themselves who are targeted, but also these houses are in built-up areas and housing estates, so the people in the area are also in danger."