Seven people are now being questioned by police about dissident republican activity.
Three men aged 47, 42 and 41 were arrested in Lurgan on Monday as part of the ongoing police operation.
Police searched three houses in the area and seized a number of items for forensic examination.
The PSNI has been granted another five days to question four people detained at four locations in counties Londonderry and Tyrone on Saturday.
A 45-year-old man arrested in the Cookstown area on Saturday has been released unconditionally.