A booby-trap bomb has partially exploded under the car of a civilian security worker in County Tyrone.
The device went off as the man drove away from his home in the Sweep Road area of Cookstown. He was not injured in the attack.
The man is a former police officer who currently works as a guard at the town's PSNI station.
PSNI Chief Supt Michael Skuce said those who planted the bomb had "scant regard" for human life.
It is the third attempted car bomb attack on security personnel in the past seven days. It was the first time one of the devices exploded.
Dissident republicans have been blamed for the attacks.
Police said the alert began at about 0800 BST on Tuesday.
The Sweep Road was closed to the Glenavon Hotel as army bomb experts examined the car but has since reopened.
A number of homes and a children nursery were also evacuated.
Chief Supt Skuce described the road where the device partially exploded as very busy, especially at that time of the morning.
"This device was designed for one purpose - to kill and injure," he said.
"This is a densely populated and busy area. We are fortunate that we are not dealing with a multiple murder here today."
Last Wednesday, a device fell from the car of an Army major in Bangor and on Saturday, a Catholic police officer was targeted in Kilkeel, both in County Down.
On Tuesday, Northern Ireland's Deputy First Minister Martin McGuinness said such attacks did "nothing to further any cause".
"There is no support for the action of these people and the complete lack of any sort of mandate for mindless attacks is in stark contrast to the overwhelming public support that exists for the institutions which the first minister and myself lead," he said.
The first minister, Peter Robinson, said those behind the bombs wanted to "bring death and destruction back onto our streets"
"As an administration, that enjoys the support of all sections of the community, we will remain steadfast in our determination not to be deterred or deviate from our course," he added.
Acting chair of the Policing Board, Brian Rea, called on the community to help the police investigation.
He said those responsible had no "concern for the community".