A controlled explosion has been carried out on a "crude but viable" device found at Belfast City Hall.
The city hall was evacuated during the alert
The building was evacuated because of the alert and an event being held there was interrupted. The area has since been reopened.
Police said that a number of items were removed from the scene for examination.
The Army has also carried out a controlled explosion on an object at Boating Club Lane in Londonderry. It was declared an elaborate hoax.
During the Derry alert police cordoned off part of Queen's Quay and Strand Road and part of the North West Institute was also evacuated.
Police said they believed the hoax device was left by the same people who placed a device outside the home of SDLP assembly member Pat Ramsey over the weekend.
Superintendent Johnny McCarroll said the devices were similar.