The 500-pound (225-kilogram) bomb, roughly the same size as the one republicans used to kill 29 people in the town of Omagh in 1998, was discovered under a bridge near Newry last Friday after two warning calls were made. The 26-year-old was detained in an early morning operation a few miles from where the bomb was found, a police spokesman said.
The bomb was discovered a week after dissidents carried out their first killing of a policeman in two years, part of a recent surge in activity by various small groups of dissident republicans. The groups are opposed to the 1998 peace agreement that largely ended over three decades of violence that claimed the lives of more than 3,600 people.
Detectives investigating the murder of police constable Ronan Kerr, 26, killed when a booby trap bomb exploded under his car outside his home in Omagh on April 2, have been given an extra six days to question suspects.
