Police on school grounds in the Los Angeles suburb of Compton are to be armed with semi-automatic AR-15 assault weapons in an attempt to prevent future school massacres.
The decision came after officers said they were not well enough equipped to deal with any attacker wielding a rifle with high capacity magazines and wearing body armour, as has been the case in several recent US school shootings.
Using semi-automatic weapons would allow them to penetrate body armour and to be more accurate than when firing with handguns, police said.
Compton, a suburb of 100,000 people in southern Los Angeles, has long been associated with gang and gun culture, although the murder rate has dropped dramatically in recent years.
The local school board, which oversees 26,000 pupils, decided to allow specially selected officers to carry the AR-15s in the back of their cars after having training.
William Wu, the Compton police chief, told the school board: "This is our objective. Save lives. [With] handguns you'd be lucky to hit accurately at 25 yards. With a rifle in the hands of a trained person, you can be go 50, 100 yards accurately."
Some students and parents, who have previously accused school police in Compton of racial profiling, expressed concern. Francisco Orozco, a recent high school graduate, told KPCC radio: "The school police have been notorious in the community and in reality have never had to shoot anyone before. So this escalation of weapons we feel is very unnecessary."
According to Mr Wu, other US school districts in California, Florida, Utah and Kansas already had police armed with semi-automatic weapons. He said: "These rifles give us greater flexibility in dealing with a person with bad intent who comes on to any of our campuses."
Ladd Everitt, spokesman for the Coalition to Stop Gun Violence, said the development was "deeply disturbing", telling Fox News: "No other free nation in the world would even consider this."