Dissident republicans are being blamed for a hoax bomb left overnight at the home of the SDLP Mayor of Derry, Cllr Shaun Gallagher.
The device was found at the back of Mr Gallagher's house in the Cappell Court area of Shantallow.
It is understood the device was found by one of Mr Gallagher's children. Ten houses were evacuated while British army experts examined the device.