The bomb found in Strabane, Co Tyrone, on Saturday was a viable mortar type device which was intended to kill police officers, the Police Service of Northern Ireland (PSNI) has said.
The police believe dissident republicans were responsible. A 33-year-old man was arrested under anti-terrorism legislation on Sunday morning and is being questioned by police.
A local resident discovered the improvised explosive device (IED) on a wall near homes in Church View, overlooking the towns police station, on Saturday morning.
The PSNI Chief Constable, Simon Byrne, said it was another callous attempt to kill or main our officers.
PSNI detective inspector Andrew Hamlin said he believed this device was placed in order to attack police officers at the nearby police station, but the bomb had the capacity to kill or seriously injure anyone in the vicinity.
This is not the first time a deadly device has been left in a public space recently and serves to remind us all how little the terrorists responsible care for the lives of local people, he said.