The North Road in Newtownards in Co. Down has been closed at its junctions with the Bangor Road and North Street.
The closure comes following the report of a gas leak in the area.
Diversions are in place but the Police Service of Northern Ireland (PSNI) is advising motorists to avoid the area.
Viable pipe bomb found in Belfast
There was further disruption in the North last night after a viable pipe bomb was found in Belfast.
Army bomb experts were called to examine a suspicious object at Forthriver Road in the north of the city.
The area was sealed off but roads have since re-opened.
The device has been taken away for forensic examination.