Police have confirmed that an object recovered from a hijacked car outside a police station in Derry was a "viable explosive device".
Last Sunday night a delivery driver was forced at gunpoint by three masked men to travel to a police station with a "suspicious object" in his car.
The incident, which occurred at around 10.30pm at Curryneirin, saw the driver forced to abandon the vehicle – a grey Ford Mondeo - outside Waterside Police Station.
Army bomb disposal experts were called to the scene and a number of homes were evacuated and an emergency shelter provided for families affected.
But on Monday, the security alert was declared an "elaborate hoax" by the PSNI.
Investigations continued and this morning the PSNI issued a statement saying the device found was a viable explosive.
Assistant Chief Constable Bobby Singleton said: "Following further technical examination of the object recovered from a hijacked vehicle outside Waterside Police Station on Sunday evening, police can now confirm it was a viable explosive device.
"This further underlines the reckless and callous disregard by those responsible for the safety of the driver, the local community and the police officers who serve them.
"I would again appeal to anyone who was in the vicinity of Milldale Crescent in Curryneirin or in the vicinity of Waterside Police Station on Sunday evening around 10.30pm, to come forward with information on 101 or through Crimestoppers on 0800 555 111."
The incident came just days after police said they believed the New IRA could be responsible for an incident in which two officers escaped injury when their car was targeted in a bomb attack in Strabane, Co Tyrone.
Yesterday evening, detectives from the PSNI Terrorism Investigation Unit carried out a search at a property in the Sion Mills area in relation to the Strabane attack.
A number of items were seized and taken away for further forensic examination.
Politicians from across Northern Ireland have condemned the recent security attacks.
Speaking during a visit to Derry yesterday, Sinn Féin vice president Michelle O'Neill branded the recent incidents "futile and reckless".
She said: "It causes nothing - only chaos and dysfunction to people of this city and also in Strabane.
"I think these actions have no place in today's society and as political leaders we must call it out when we see it.
"This could have had catastrophic implications. We could have had the loss of life of two police officers.
"These people are in conflict with the community in which they live."
With additional reporting from PA