Police have released photographs of the Brexit day bomb they believe the Continuity IRA (CIRA) was responsible for.
A bomb was found attached to a lorry in Lurgan, County Armagh, on Tuesday morning.
It is thought the device may have been intended for a Brexit day attack.
Police said they first received a report about an explosive device in a lorry at Belfast docks on 31 January – the date the UK left the EU.
It was claimed the lorry was due to travel by ferry to Scotland.
A search was conducted but nothing was found.
“These images clearly show the explosive device attached to the lorry,” said Det Supt Sean Wright.
“They also demonstrate the sheer recklessness of those who knowingly put the driver, road users and the wider public at risk of death or serious injury.”
Police have not yet given an indication of the size of the bomb, but it is understood the lorry did not leave the industrial estate between the times of the two calls.
They said they worked with a haulage company, which owns the lorry, to search about 400 vehicles and locate the explosive device.
It was made safe by ammunition technical officers (ATOs).