Three pipe-bomb-type devices were found by police a short distance from an explosion outside a family home.
Army bomb squad officers examined a number of suspicious objects following searches in the Parkhead Crescent area of Newry.
A PSNI spokesman said the Parkhead search was part of an investigation into serious crime.
The devices, along with a quantity of ammunition, were found close to where a pipe-bomb was thrown in the Patrician Park area of the city.
Chief Inspector Davy Beck said: "I am happy that these potential pipe-bomb type devices and ammunition have been taken off the streets of Northern Ireland.
"The public can rest assured that we will continue to serve the community of Newry."
Security services were called after a device went off at the front of a property where a father was at home with his wife and three children at around 9.20pm on Wednesday. Nobody in the house was hurt.
The distressed father-of-three said his family was left badly shaken by the attack.
It caused damage to part of the house and a car parked in the driveway.
The PSNI said a motive for the attack had not yet been established and appealed for anyone with information about it to contact officers.
Alliance MLA Stewart Dickson said: "The people responsible have no regards for the consequences of their actions.
"There is no place for violence on our streets. We should be thankful that nobody was hurt in this attack."
He added: "Having found devices, I hope they will be able to trace the source and the maker of them and that will help them bring forward a prosecution."