Shots were fired at a house in Limerick overnight and a second house was damaged by what gardaí believe may have been a pipe bomb.
A number of shots were fired at the front door of a house on Hyde Road.
There were people in the house at the time, but no one was injured.
Elsewhere, gardaí are investigating an explosion at a house in Bengal Terrace, in the east of the city.
It is believed that a pipe bomb may have been thrown at the house.
The scenes have been sealed off for technical examination.