An investigation is under way into "criminal damage" at a house in Drogheda in Co Louth.
It is understood two devices were thrown into the downstairs of the house at Ballsgrove in the town and exploded just after midnight.
A married couple and their two children, aged three and six, were upstairs at the time of the incident.
They all managed to escape the subsequent blaze unharmed.
Gardaí say they are investigating the cause of the fire and the scene is being preserved.
No arrests have been made.