The army bomb disposal team has dismantled two viable pipebombs in Fairview Park in Dublin.
A third device was discovered last night in Ronanstown during a planned search by gardaí.
The devices in Fairview Park were discovered in bushes by a man out walking his dog at around 8am.
Members of the Army Explosive Ordinance Disposal Team were called to the scene shortly afterwards.
Fairview Park has been reopened to the public and garda forensic experts are now investigating the remnants of the devices.
Nobody was injured during the operation. A spokesman for the Defence Forces said it is not clear who was responsible for the devices.
The Ronanstown device was similar to the ones discovered in Fairview Park.
Gardaí are appealing for anybody who saw any unusual activity in the Fairview Park area to contact them at Clontarf Garda Station on 01-6664800.