NEWARK — Gov. Chris Christie said Friday that posting armed guards outside schools won’t make classrooms safer or encourage learning, warning against turning schools into armed camps.

For such a plan to be effective from a law enforcement perspective, the Republican governor said, armed officers would have to be positioned outside every classroom, not just at the front entrance, because there are many ways to enter a school.

“You can’t make this (school) an armed camp for kids,” said the governor, who is a former federal prosecutor.

Christie stopped short of commenting directly on the National Rifle Association’s proposal, prompted by the Connecticut elementary school massacre, that armed guards be stationed in every American school to stop the next killer “waiting in the wings.” Christie said he hadn’t yet read the proposal.

The state’s largest teachers union, however, sharply criticized the NRA plan.

“We’ve got to eliminate access to these military-style weapons whose only purpose is to kill human beings,” Steve Wollmer, spokesman for the New Jersey Education Association, told The Associated Press. “The answer isn’t to create battlegrounds in our school hallways. That’s insanity.”

He also cited the expense. It would cost $10 billion a year if each of the nation’s roughly 100,000 public schools spent $100,000 to pay the salary, benefits and equipment costs for an armed guard, he said.

Armed police officers are already posted in some New Jersey schools, mostly high schools.

The 600 officers trained by the New Jersey Association of School Resource Officers not only investigate crimes and provide some security, but they also serve as mentors to students, said State Police Sgt. Gregory Williams, a member of the association’s executive board. He did not know the exact number of schools with an armed police presence.

Christie has called for a thoughtful dialogue on gun violence, mental illness and exposure to violent video games.

He also said it’s up to police to make sure New Jersey gun laws are enforced. New Jersey’s laws are considered the second toughest in the country, behind only New York’s.

Christie noted the success of a recent gun buy-back program in reducing the number of weapons on the street.  A two-day buy-back in Camden last week brought in 1,137 weapons, so many that the program’s initial $110,000 budget was exhausted with hours left in the event and had to be replenished.