An explosive found in a busy shopping district in the North may have fallen from a vehicle, police have said.
The device was discovered in Market Place, Lisburn this afternoon, forcing businesses to be evacuated and streets closed as a controlled explosion was carried out.
A vehicle was later seized by detectives in the Lagmore area of Belfast.
The explosive was described by police as viable and was taken away for forensic examination.
Superintendent Brian Kee said: "Our investigation into the circumstances surrounding this security alert is at a very early stage. We are following a number of lines of inquiry, one of these is that the device may have fallen from a vehicle."
The Market Place area of Lisburn was shut down for several hours while bomb squad officers examined the scene.
Mr Kee added: "The device was discovered in the centre of the city on a busy Saturday afternoon where, had it exploded, it could have killed or injured anyone in the vicinity.
"This completely reckless act not only endangered members of the public but also caused mass inconvenience and disruption. Those responsible for this device have shown total disregard for the safety of the community."
Police have appealed for anyone with information or anyone who saw anything suspicious in the Market Place area of Lisburn to come forward.