Officers carried out the searches at Foxes Glen in Dumurry and Hamill Street in Belfast City Centre.
Detective Inspector Stuart Griffin said: “A number of items have been recovered from two properties and will be taken for further examination.
“Two men aged 37 and 48, and a woman aged 35 have been arrested.
“They have been taken to the Serious Crime Suite at Musgrave station for questioning.
“There are no further details at present.”
Police have not yet said whether the searches are linked to several shootings in west Belfast carried out by dissident group ONH including the murder of Joe Reilly last week.
Or if this was an intelligence-led operation to prevent further attacks.