Police investigating an armour-piercing projectile device, discovered in west Belfast in October, have arrested four men.
A new dissident group claimed responsibility for the 'explosively formed projectile' (EFP), discovered on Pantridge Road in Poleglass following a three day security alert last year.
A group calling itself Arm na Poblachta said they had left the viable device in the area in an attempt to attack the PSNI.
While police had previously confirmed the existence of the group, it was the first time the organisation claimed responsibility for a device.
The PSNI said at the time it was a form of horizontal rocket designed to kill police travelling in armoured vehicles.
Detectives from the Serious Crime Branch arrested three men aged 21, 34 and 60 in Belfast yesterday and a 29-year-old in Dungannon.
Detective Inspector Adrian Brown said: "The device, which was explosively formed projectile - EFP - a weapon that is primarily designed to attack armoured vehicles and kill the occupants within, caused widespread disruption at the end of last year.
"While it was clearly designed to kill or seriously injure police officers serving the local community in west Belfast, it was left in a position where there was every possibility that it could have killed or maimed members of the public.
"Those responsible showed callous disregard for the safety of members of the public and police officers and we were extremely fortunate that no one was killed or seriously injured.
"If anyone has any information about this incident please contact detectives on 101 or alternatively information can also be provided to the independent charity Crimestoppers on 0800 555 111."
