"People of a very young age" have been at the centre of an upsurge in sectarian disturbances and attacks, Chief Constable Sir Hugh Orde has said.
A primary seven classroom was destroyed in a fire
He told a Policing Board meeting in Ballymena that sectarianism "was a problem far wider and more complicated than a simple policing solution".
He was speaking following arson attacks on two Catholic schools in the town, the latest in a spate of incidents.
Extra officers have been drafted in to the area to protect property.
Thirty police officers have been involved in the fresh security operation to prevent sectarian attacks.
Operation Striker covered 50 Catholic-owned properties, churches, schools and GAA sports grounds.
Vehicle checkpoints were set up in Ballymena, Ahoghill and Portglenone. Mobile patrols covered other locations.
SECTARIAN ATTACKS IN BALLYMENA 1 MARCH - 31 AUGUST
5 arson attacks, all on Catholics (2 considered as attempted murder)
4 petrol bombs: 2 Catholic, 2 Protestant
5 sectarian assaults: 2 Catholic, 3 Protestant
8 paint attacks: 7 Catholic, 1 Protestant
13 criminal damage: 9 Catholic, 4 Protestant
7 intimidation: 3 Catholic, 4 Protestant
Total incidents: 42. Catholic: 28; Protestant: 14
In the village of Ahoghill, there have been 15 sectarian attacks on Catholics.
Sir Hugh told the Policing Board public meeting: "Much of the disorder on the small number of parades where disorder occurred we saw was being perpetrated by people of a very young age.
"In other words, what we have been seeing is a trend across a number of events where police officers or communities are attacked, where very young people are engaged in criminal activity."
The Policing Board holds the Police Service of Northern Ireland to account.
Supt Terry Shevlin said more resources have been deployed
Ballymena district commander Chief Superintendent Terry Shevlin told the same meeting that police had identified a problem with sectarian violence in the area as far back as March.
Mr Shevlin said that to reduce the violence, more community beat officers had been deployed, there were covert operations and technical operations such as using police cameras and equipment, CCTV, intelligence gathering and forensics.
He said he had also had to contend with tensions around parades, public disorder in the Dunclug area of Ballymena, the loyalist UVF-LVF feud, and using police resources to keep rival nationalist and loyalist youths apart.
He said that in the two weeks between August 15 and 30, before the two recent attacks on Catholic primary schools in Ballymena, there had been only one significant attack on a Catholic property in Ahoghill and one attack on a Protestant property in north Ballymena.
Speaking earlier, the board's vice chairman, Denis Bradley, said that while the policing response was important, it alone could not solve the problem of sectarianism.
"The police have to answer for their operational ability and that's fair enough," he said.
"But civic society and churches and politicians and everybody else need to do something about this nihilism, on the one hand, among youngsters, 14, 15, 16-year-olds, because that's what it is feeding into our old problems of sectarianism.
"Plus the adults, the 20 and 30 year olds who are quite sectarian in the sense that they can't live with their neighbours. Police can't solve all of that."
Fred Cobain, an Ulster Unionist member of the Policing Board, said: "I think the police in most circumstances do an extremely good job.
"Society itself has responsibilities to bear."