Loyalist paramilitaries have claimed they planted a pipe-bomb at a Catholic girls' school in north Belfast which was at the centre of a lengthy loyalist protest just over a year ago.
The device was discovered at the front gates of Holy Cross Primary School in Ardoyne at around 8 a.m. yesterday.
It was later made safe by British army bomb-disposal experts. Pupils were forced to use an alternative entrance.
In a statement, the Red Hand Defenders - a cover-name for the UDA - said they planted the bomb. Father Aidan Troy, the chairman of the school's board of governors, said: "This is a frightening development.
"We thought we had left all of this behind but this is horrific. Some of the children didn't come to school because of the alert."
He said it was disappointing that the new school term had begun this way. It had been "very fortunate" that the bomb was discovered before any children had arrived at the school, he added.
Local Sinn Féin Assembly member, Mr Gerry Kelly, said: "The new year has only begun and already we have a disgraceful attack on children by some faction of the UDA.
"This attack is a cynical attempt by the UDA to draw attention away form the fact that they are involved in an internal feud."
Unionist politicians and community workers must do everything possible to end such attacks, he said.
"In recent days, we have seen unionist politicians be highly outspoken in their calls for loyalists to end their feud. Unionists need to be as vocal in their calls for attacks upon nationalists to end."
Local DUP MP, Mr Nigel Dodds, strongly condemned the attack.
"All schools should be places free from any form of violence or threat of violence. It is outrageous and totally unacceptable that anyone in society would endanger the lives of school children, relatives and teachers through this type of action.
"Those who carried out the planting of the bomb device do not represent the overwhelming majority of the Protestant and unionist community in north Belfast."
Local SDLP Assembly member, Mr Alban Maginness, described the attack as cowardly. "The repeating targeting of innocent children is simply vile, and nothing can be gained from it.
"It is saddening that when the situation had finally calmed down some people have taken it upon themselves to fan the flames of sectarian hatred in north Belfast."
Holy Cross was at the centre of a bitter loyalist protest which ended in November 2001.
A three-month protest by Protestant residents of Glenbryn led to pupils being escorted to and from the school by the security forces.
It ended after the loyalists were promised social improvements and new security measures.