A gang of balaclava-clad youths terrified students in a south Dublin school after showing up brandishing sticks.
The terrifying incident unfolded in De La Salle College, Churchtown on Monday with the gang allegedly looking for a particular student in the school.
The group left the scene before gardai arrived with one worried mum telling how her son witnessed the whole event.
Children were were rushed back into a classroom by anxious teachers until the area was safe.
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The woman told The Irish Sun: "The school finished and two of them were kept inside in their classes - but one of them came out as normal and wandered into a situation where these kids on bikes with weapons - sticks - were approaching the school on bikes.
"He said they had black balaclavas on and black tracksuits. The gardai were called and then the armed response team turned up."
The concerned mum added that her other child "was rounded up" with their year group and put in a classroom.
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She said: "When my youngest came in and told me what he had seen... I was just shocked. Absolutely shocked that it could have happened."
The principal of De La Salle College said: "I understand that the incident occurred in the locality after school hours.
"Most of our students had left for home, those remaining were requested to stay in the school pending clarification from supervising staff that the youths had dispersed."