The serving soldiers, one male and one female, were arrested in Donegal under section 30 of the Offences against the State Act.
The move by gardaí came less than 24 hours after a pipe bomb was discovered at a premises in Burnfoot. Officers sealed off an area adjacent to a petrol station after a tip-off. After a number of hours, gardaí removed what was described as a “viable device” from a flat in the area.
The soldiers are being quizzed about that incident, and also alleged links to a dissident republican group.
It is understood the Defence Forces have been assisting gardaí with their investigations in recent weeks.
The pipe bomb probe is also being linked to the discovery of a similar device at Letterkenny Garda Station last year.
Gardaí are also investigating if the find is linked to a row between two small groups of individuals within the defence forces. One of those groups has claimed it is linked with a dissident republican group in Derry.
It is understood that the pipe bomb found yesterday, although viable, was cruder than most such devices linked to dissidents.