Ten families were ordered to leave their homes in the south inner city early this morning after a pipe bomb was thrown at a flat.
The alarm was raised in the Mary Aikenhead complex on Basin Street Lower when the device was found by the flat owner after it was thrown at the property.
Gardai said the army bomb squad were called in after officers looked at the device shortly after 5am this morning.
The Explosive Ordnance Disposal (EOD) unit of the army arrived at the flats complex at 6.30am and residents living near where the device lay were asked to leave the courtyard.
Dozens of residents gathered on the street, many in their nightclothes, and waited patiently as the bomb squad evaluated the device.
They used a remote-controlled robot to carry out an initial inspection.
A garda on duty said the suspect device was cylindrical in shape and resembled other devices that have been used by criminal gangs in Dublin in the recent past.
"We just thought we should be sure about it before it was moved and called in the EOD to look at it just in case," he said.
The pipe bomb broke a pane of glass in a double-glazed window but failed to break the second pane.
The device was believed to be a viable one that could have caused serious injury or death if it had exploded in the flat.
No controlled explosion was carried out on it, but it was instead removed to a military installation for further examination.
The bomb squad also dealt with a device last night in Limerick. It is believed the device was found by accident after being hidden.