Bombings by dissident groups last year left no one seriously injured [File: EPA]

Army bomb-experts in Northern Ireland have defused a 225-kilogramme van bomb near the Irish border.

The bomb, hidden underneath a motorway bridge near the main Dublin-Belfast road, was rendered inactive on Saturday following an 18-hour operation.

Police said that the bomb had been set by dissident Republicans to cause "huge devastation" in the nearby town of Newry ahead of Northern Ireland's election campaign.

They said that it had likely been abandoned short of its target and before it could be detonated.

Two warning calls were made to police about the bomb on Friday.

"In this case, this bomb may have been on its way to the centre of the town," David McKittrick, Ireland correspondent for the UK's Independent newspaper, told Al Jazeera.

"The security forces were successful in stopping that happneing, but at the same time they weren't successful in preventing the making of the bomb and there were hold-ups, once the bomb was discovered, in clearling the area."

There was no immediate claim of responsibility for the bomb, but police said a phone call to warn about the bomb used a code word previously used by dissident Republicans.

Impatient motorists

Police shut the road following the discovery of the bomb, but impatient motorists unwilling to take a diversion moved the traffic cones and "road closed" signs.

BBC Northern Ireland footage showed dozens of cars driving directly past the van before police reinforced the barriers.

The bomb was double the size of those used in a number of bombings last year by Irish Republican Army (IRA) dissidents, none of which caused serious injuries.

Recent weeks have seen a surge in activity by IRA dissident groups opposed to the 1998 peace agreement which largely ended three decades of violence that killed more than 3,600 people.

A week ago Ronan Kerr, a 25-year-old police constable, was killed when a bomb exploded under his car in Omagh, an attack police suspect was organised by IRA dissidents to scare Catholics from joining the north's police force.

The killing prompted a public outcry in Ireland.

Detectives said they had detained a 33-year-old near Omagh on Friday night in the third arrest connected with the murder.