Gardaí are appealing for witnesses after a device exploded under a vehicle that was parked outside a house at Manor View Park, Letterkenny, Co Donegal.
Gardaí say nobody was injured in the incident, which took place at about 4am this morning.
The area was evacuated and remains sealed off for technical examination.
An Explosive Ordnance Disposal team is due to attend the scene.
Gardaí have appealed for witnesses or anyone with information to contact Letterkenny Garda Station on 074-916 7100.