Dissident republicans suspected of planting a car bomb at a courthouse in the North were intent on causing murder and destruction, the Stormont Justice Minister has said.
David Ford spoke after police confirmed the device abandoned in Derry contained 50kg of homemade explosives packed into a beer keg which had been left in a stolen Vauxhall Astra.
Dozens of elderly residents were moved from a sheltered housing development in the city as a security operation was launched around the Bishop Street area after a telephone bomb warning at 6.45pm yesterday.
Choirboys, some as young as seven, were told to get out of the nearby St Columb's Cathedral, while hearings at the courthouse have been moved to other courts.
Mr Ford said: "It is clear that those responsible for this attempted bomb attack were intent on causing murder and destruction and I wholeheartedly condemn their actions. I am very thankful that no-one was injured.
"It is particularly sad to note that it was some of the most vulnerable people in our society, children and the elderly, who were most disrupted by this incident.
"I very much welcome the co-operation from the local community during what I am sure has been an anxious time and I am confident that the people of Derry will stand in unison to condemn this attempted attack on their city."
He appealed for anyone with information on the attempted bombing to come forward to the police.
The police district commander, Chief Superintendent Stephen Martin, said dissident republicans from either the Oglaigh na hÉireann or Real IRA groups were suspected to be responsible for the bomb.
He added: "Unfortunately there is no such thing as complete security. The difficulty we face is that while we have a number of people, albeit they are small in number, who are willing to set their faces against the wishes of the majority, unfortunately we will see some acts like this occur again."
The police said the car, a green Astra with the registration V594 EBF, was stolen on Sunday in Derry. They appealed for anyone with information to come forward.
It is two years since the threat from dissident republicans in Northern Ireland was escalated to severe. The groups have been particularly active in the Derry area.
Foyle MP Mark Durkan said: "This was a viable device which seems to be on a significant scale ... If those behind this think they are doing something to damage the legal system, they are not. They are just damaging the people of Derry - damaging their daily lives as they go about their business in these very difficult times for everyone."
After a number of controlled explosions were carried out on the device, Sinn Féin Assembly candidate Martina Anderson said the bombers offered nothing for the future.
"The people's focus will be back on building for the future as soon as the debris is cleared but you will still be stuck in the past with not a progressive thought between you. So get real, pack up your tent and go home," she said.
"The peace and political processes will continue to strengthen in spite of the wreckers."