Three children aged 8-10 have been arrested after a Catholic school was badly damaged in County Antrim.
Damage to St Mary's on the Hill Primary School at Carnmoney included 41 broken windows. Graffiti was also daubed over the buildings.
Headmaster Patrick Kennedy maintained the incident did not reflect the attitudes of young people in the area.
"I think it's important to keep this in perspective - we are talking about a small minority of children," he said.
District commander Supt Will Kerr described the arrests as "a timely and proactive response" by police.
"We will not tolerate these completely senseless and mindless acts of wanton destruction," he said.
"This school has been targeted in the past and due to these previous incidents local officers have been closely monitoring the area."
He added: "These arrests were as a result of a timely and proactive response by the local crews and we want to make it clear that we are concentrating resources and working closely with the local community to help combat this type of anti-social activity."
The mayor of Newtownabbey, Alliance councillor Lynn Frazer, said she condemned "those involved in such incidents".
"Those who lead young children astray and prompt them into committing sectarian acts are an absolute disgrace," she said.
"People should be setting a positive example for young children, not instilling prejudice and hatred in them."