Police in the North have been granted more time to question six people arrested during during an operation against dissident republicans on Monday.
Four out a total of 10 people detained in raids in counties Armagh and Fermanagh have been released without charge.
The PSNI said it had disrupted a "major terrorist conspiracy" to procure arms after arresting the ten.
Eight premises were searched during the raids, which involved some 200 police officers supported by the British army.
One of those arrested was being questioned about the 1998 Omagh bomb attack.
Police said the operation targeted dissident republican activity in both the United Kingdom and Europe. The operation followed a joint investigation between the PSNI's Crime Operations Department and the British security service.
Police confirmed part of the operation was aimed at disrupting a conspiracy to procure a significant quantity of arms.
Detectives from the Crime Operations branch travelled to France and were present during related searches carried out by French police. The inquiries in Europe are continuing.