A suspected device was located during a proactive search by the Paramilitary Crime Task Force (PCTF) at a property in the Dee Street area on east Belfast on Monday 22 August.
The item was examined by ATO, made safe and removed for further forensic examination.
A number of other items, including a quantity of suspected class B drugs, were also recovered during the proactive search by PCTF officers investigating the activities of the West Belfast UDA.
A man aged 31 and a woman aged 33 were arrested under the Terrorism Act and remain in police custody.
Two further linked searches took place at properties in south Belfast and east Belfast, where a number of other items including a small quantity of class B drugs and electronics, were seized.