Two Irish soldiers have been arrested in connection with alleged dissident republican activity and the discovery of a pipe bomb in County Donegal, it has emerged.

The serving members of Ireland's defence forces – a man and a woman – were detained on Tuesday.

The arrests followed the discovery less than 24 hours earlier of a viable pipe bomb device close to a petrol station in Burnfoot, not far from the Northern Ireland border.

Gardaí are questioning the pair over alleged links with the new IRA over the border in Derry. But the Garda Siochána is also pursuing an alternative theory centring on a row between soldiers.

The pipe bomb investigation is also being linked to the discovery of a similar device at Letterkenny police station in Co Donegal last year. Forensic experts are examining the device found on Tuesday for similarities.

The two soldiers are being held under the Irish Republic's anti-terrorist legislation, section 30 of the Offences Against the State Act, and can be questioned for up to three days.