Police have carried out a number of searches and made arrests in Coalisland and Lurgan as part of an operation against dissident republican terrorist activity.
A 46-year-old man was arrested in Coalisland and is being questioned at a Belfast police station.
Police swooped on Wednesday and evacuated a number of houses in the Woodville Avenue area of Lurgan as part of the operation.
A PSNI spokesman said: “Police have conducted a number of searches at properties in the town [Lurgan] this morning and four men have been arrested. Two are 22 years old, one is 24 and the fourth is 46.”
Sinn Fein MLA Catherine Seeley condemned the disruption in Lurgan, which she said was caused by a suspect device.
The Upper Bann MLA said: “This security alert and house searches has brought nothing but disruption to the local community in the Kilwilkee estate.
“Residents in Woodville Drive have had to be evacuated from their homes while others have been forced to stay inside their homes rather than pass by the suspect device.
“This incident serves only to cause fear and disruption and achieves nothing.”