A viable letter bomb has been discovered at a postal sorting office in Londonderry.
Police confirmed the device found in the Great James Street facility yesterday afternoon was viable.
It was contained in a white A4 envelope with the address written in grey using a stencil.
Stormont Justice Minister David Ford condemned those responsible.
“Yet again we have a cold blooded attempt to cause death or serious injury,” he said.
“Those behind this device do not care who they hurt or injure and have nothing positive to offer.
“I would ask people to continue to be vigilant and report anything suspicious to the police.”
Last month a series of letter bombs sent to Army recruiting offices in England were blamed on dissident republicans opposed to the peace process.
In October last year dissidents sent a series of letter bombs to high profile political and security figures in Northern Ireland.
One of the devices was addressed to the seat of power sharing executive at Stormont Castle in Belfast addressed to Northern Ireland Secretary Theresa Villiers.
Another bomb was delivered to the offices of the Public Prosecution Service in Derry while two explosive packages - one addressed to Police Service of Northern Ireland (PSNI) chief constable Matt Baggott and the other to one of his senior commanders - were intercepted at Royal Mail offices in Belfast and Lisburn.
The spate of letter bombs has marked the re-emergence of a terror tactic that was used by paramilitaries during the Troubles.