Nearly all campus police officers at public universities now carry guns, pepper spray and other weapons, according to a new Justice Department report, and experts say more private schools are looking to arm police.

The Bureau of Justice Statistics surveyed more than 900 four-year colleges with at least 2,500 students. Findings released Tuesday show that overall, about two-thirds of public and private campuses used armed officers during the 2011-12 school year. Officers at public universities were more than twice as likely as those at private schools to carry guns.

Despite the increase, schools aren't required to report weapon use to federal authorities.

Experts say campus administrators are increasingly being pressed for assurances that officers are well-equipped and well-trained following high-profile crimes like the 2007 Virginia Tech shootings.