Police searched 400 vehicles in bid to find deadly device which was located in Co Armagh
The PSNI have said they believe a bomb bound for a ferry to Scotland was planted by the Continuity IRA.
The bomb was discovered on a lorry on Tuesday at a commercial premises in Lurgan.
Elsewhere, Belfast Harbour Police were in attendance at Clarendon Dock on Thursday night.
Several Harbour Police vehicles were seen entering the dock and searching lorries, however it is unclear if the operation is connected to the Lurgan incident.
Assistant Chief Constable George Clarke declined to give specific details on the Lurgan bomb find, but said it was a viable device that could have caused death or serious injury.
He said a warning call was made to a media outlet last Friday, warning that a device had been left in a trailer in Belfast docks.
The lorry trailer had, in fact, never left Lurgan and remained undiscovered over the weekend.
The call was also claimed the bomb would explode on a midnight ferry, which did not exist.
Police at this time carried out a search on a ferry that left Belfast at around 11.15pm.
"It's very important to note that information was exceptionally sparse and limited. There was a police response in relation to that," ACC Clarke said.
I strongly condemn the actions of those who placed a bomb on a heavy goods vehicle in Lurgan. Their reckless attempt to cause serious harm to the public and damage to the business community will not stand. The community are united against these actions.— Simon Byrne (@ChiefConPSNI) February 6, 2020
A further call was made to same outlet on Monday with "substantially more detail".
This gave the name of a commercial haulage company, indicating the device had been left on a trailer connected to the company.
It was also claimed the intention was for the device to explode on Friday evening around the time the United Kingdom left the EU.
The PSNI worked with the owners - carrying out "a substantial clearance and investigative operation" - to identify the vehicle in Lurgan, discovering the device on Tuesday.
ACC Clarke said the second call indicated the bombers had intended the lorry would travel to Belfast.
He said those responsible needed to explain their exact intentions, but that they had "recklessly and callously" sought to put the device "on a public road, in a public place and expose members of the public to a very real risk of harm and death".
He confirmed the PSNI believe the dissident republican group, CIRA, made both warning calls and were responsible for planting the bomb.
ACC Clarke added there would be an increased security presence around ports in Northern Ireland as well as "covert activity" to keep people safe.
The potential damage which could have been caused and loss of life either here in Northern Ireland, on board a ferry or in Great Britain do not bear thinking aboutDUP leader Arlene Foster
He also stressed the risk to life caused by leaving the bomb undiscovered for days.
"During that period of time, a viable bomb is in a commercial yard posing significant risk to anybody who comes within range of it."
DUP leader Arlene Foster said the discovery of the bomb highlights that there are those in Northern Ireland who "still attempt to drag us backwards into terrorism and violence".
"We understand there will have been good operational reasons that more details were not made public until now, but those that information is an even more chilling reminder of the threat posed by these terrorists," she said.
"The potential damage which could have been caused and loss of life either here in Northern Ireland, on board a ferry or in Great Britain do not bear thinking about.
"It is significant that information was available which meant police could search the ferry and ensure it was able to sail safely. The disruption of such potential attacks can save lives and we owe a huge debt of gratitude to all those working to keep the public safe and thwart the efforts of terrorists."
At a meeting of the Northern Ireland Policing Board today, the UUP MLA Alan Chambers added his "condemnation and outrage" to the incident.
“You talk about that if it had exploded on the M1 or the Westlink or the harbour estate the risks posed to not bear thinking about," he said.
We could have been in a catastrophic position here and we need to realise that. It may have been the worst-case scenario but it's a possibility that that's what would have happenedSinn Fein MLA Gerry Kelly
“The possibility was that had it been loaded onto that ferry and exploded at sea the consequences could have been horrendous.”
Speaking after the meeting, the DUP MLA Mervyn Storey said: “There are still organisations out there who have the intent and capability of carrying out these type of atrocities.
“On the information they have given us to date, clearly there was intent to have a viable device that was going to cause some disruption and if possible to take life. I think it is very serious."
The SDLP MLA Dolores Kelly said the terrorists had shown "complete wanton disregard" for the safety of the community, including lorry drivers and ferry passengers.
“These people couldn't care less and then for it to end up in an industrial estate in close proximity to a residential area and over so many days," she said.
“If the dissidents or whoever was responsible, and I believe that it was dissidents, had any greater concern for the people then it wouldn't have taken them three days to give more specific details about where the bomb was attached to to have helped the police, if they were putting people first.
“That's never their consideration and they have learned no lessons from the Omagh bomb where there was misinformation. It's appalling and it's such evil."
Sinn Fein MLA Gerry Kelly said: “They believe it was dissidents. This trailer could have been on a ferry and you can imagine how many people would be on a ferry if it have of went off in the middle of the sea.
“We could have been in a catastrophic position here and we need to realise that. It may have been the worst-case scenario but it's a possibility that that's what would have happened."
He added: “All elected representatives are one voice over this and condemnation came collectively from the board. I am adding to that condemnation personally and also as a spokesperson for Sinn Fein, they need to desist and they need to move away.
“If anybody has any information about this, they should hand it over to police.”