A British Army technical team have removed a device from a house in Armagh for examination.
It was thrown at a house at Hamiltonsbawn Road, on the outskirts of the city, at around 2 a.m. last night. An RUC spokesman described it as a "crude but lethal" bomb
The occupants of the house, a female babysitter, a four-year-old boy and 18-month-old girl, were unhurt.
The RUC are trying to determine a motive for the attack.