Shell Ireland is describing the discovery of an explosive device outside its offices in Dublin as a "sinister development".
The Republic's Army Bomb Disposal Unit had to be called in to deal with the device outside Corrib House on Leeson Street at about 10.30pm last night.
A controlled explosion was carried out, and the scene was given the all clear at 11.20pm.
"The bomb disposal team received a Garda request to attend at the scene," said a Defence Forces spokesman.
"The team carried out a controlled explosion on the simple, improvised explosive device.
"The bomb disposal officer gave the all-clear at 11.20pm. The remains of the device were handed over to Gardai at the scene for investigation into the incident."
The area around Leeson Street and Adelaide Road was sealed off but was given the all-clear at around midnight. Shell Ireland is building a controversial pipeline despite local protests at Rossport in north Co Mayo.
In a statement released today, Shell says the work being undertaken on the Corrib pipeline in Mayo has all the necessary consents and permissions required.
The company goes on to say that this is a time for calm assessment and that they remain open and willing to talk to any individuals or groups who still have concerns about the project.