The police have uncovered a substantial arms find and a notebook containing information about the security forces.
An AK47 assault rifle was recovered
It is believed the haul is connected to the Continuity IRA.
The police said they carried out eight house searches over the past few days as part of an ongoing investigation by the Organised Crime Branch.
During the raids - thought to be in west Belfast - they seized three vehicles, an AK47 assault rifle and five real and replica handguns.
A shotgun and a quantity of ammunition were also recovered.
They also seized component parts of an explosive device and a notebook containing personal details of security personnel.
It is understood the find is connected to two arrests for alleged extortion in the Dargan Road area of north Belfast on Monday.