Police believe a fire in Keady, County Armagh, at the weekend was an attempt to lure officers into an ambush and is linked to an ongoing bomb alert.
A number of families have been moved from their homes after a suspect object was found on the town's Castleblayney Road on Tuesday.
Just after midnight on Sunday a section of fencing in the area was set alight before being put out by firefighters.
Police have appealed for information about both incidents.
Six houses have been evacuated after a beer keg which had wires attached to it was found by a member of the public on the Castleblaney Roadon Tuesday.
It is understood a bomb warning was received the day before.
Army bomb experts and police remained at the scene overnight.
Police cordoned off a five-mile stretch of road after the object was found.