There have been no reports of injuries after a blast occurred in Newry, the PSNI has said.
A security alert was triggered by the discovery of the already detonated device near Barracric Road in Newry.
The railway line between Newry and Dundalk was closed as British Army bomb disposal experts examined the scene.
PSNI Inspector Lorraine Dobson on Thursday night said no damage was caused and there had been no reports of any injuries.
“I would like to thank the public for their co-operation during this operation,” she said.
She asked for anyone who had noticed suspicious activity in the area over recent days to come forward.
The incident is the latest in a series of violent attacks in the last two weeks.
Dissident republicans opposed to the peace process have been blamed for the spate, with the upsurge in activity believed to be an attempt to disrupt the British general election.
Bombs have detonated near Army and Probation Office facilities in Derry, while in north Belfast there have been two attempts to blow up police officers.
There have been no injuries.
Sinn Féin representatives have also been targeted, with some subject to death threats and bomb warnings.
The home of the party’s Deputy First Minister Martin McGuinness was hit by paint bombers and cars belonging to other members were torched.
Officers have stepped up patrols in a bid to thwart the extremists.
Press Association