A pipe bomb exploded outside a house in Ballymena, Co Antrim, last night.
The incident occurred at the front of property on the Antrim Road at about 10.45pm.
The PSNI said that there was minor damage to the front of the building, but no one was in the house at the time of the attack. A number of items have been removed from the scene for further investigation.
Appealing for information, the PSNI said that a group of men had been seen running in the direction of the Ballee estate shortly after the attack took place.
Police in Co Antrim recently issued pictures of pipe bombs as a warning to the public not to inadvertenly pick up such devices. The warning follows a number of pipe bomb attacks in the area.
Last Friday, two men escaped injury when a pipe bomb was thrown through the window of a house at Carnbrook Drive in Antrim.