The PSNI say that an object left at a Carrickfergus house was a viable explosive device.
It was discovered outside the house in the Marshallstown Road area of Carrickfergus, the main road running along the north-eastern edge of the town, at around 10.30pm on Saturday.
Police announced details of the security incident at midday on Sunday.
In a statement, Chief Inspector Simon Ball said: “The resident of the house reported hearing a bang and saw a flash at the front of his house and initially thought that a firework had gone off.
“He was the only person in the house at the time and, although he was not hurt, he was left shocked by the incident.”
After the object was discovered, a controlled explosion was carried out.
The device was later declared a viable device, but was found not to have detonated.
The PSNI added: “This was a reckless attack in a residential area and, had the device exploded, it could have caused serious injury or even death.”
A number of roads in the area were closed and residents had to be evacuated from their homes for a time.
if you saw anything or know anything, contact police on the non-emergency number 101, quoting reference 1617 of 25/8/18.
Alternatively, call independent charity Crimestoppers on 0800 555 111 which is 100% anonymous.