SACRAMENTO (AP) — County jails that account for the vast majority of local inmates in California have seen a marked increase in violence since they began housing thousands of offenders who previously would have gone to state prisons.

Many of the 10 counties that account for 70 percent of California’s total jail population have experienced a surge in the number of inmate fights and attacks on jail employees, according to assault records requested by The Associated Press.

The spike corresponds to a law championed by Gov. Jerry Brown in which lower-level offenders are sentenced to county jails instead of state prisons. Some jails have seen violence dip, but the trend is toward more assaults since the law took effect on Oct. 1, 2011.

Brown sought realignment of the state’s penal system in response to federal court orders requiring the reduction of prison overcrowding as the main way of improving medical and mental health treatment for state inmates. But the change has shifted many of the same problems the state had experienced to local jails.

Nearly 2,000 more jail inmates were assaulted by other inmates in the first year after the realignment law took effect, up about one-third over the previous year, the figures compiled by the AP show. Attacks on jail employees increased by 165 during the same period.

A rise in the level of violence in jails was likely to be inevitable under the law because of the higher number of additional felons being sentenced to counties.

Yet the increase significantly outpaces the overall growth in the jail population for the 10 counties surveyed during the same time period. On average, the combined population grew 14 percent through 2012 while inmate-on-inmate assaults rose 32 percent and inmate-on-staff assaults rose 27 percent.

By June, the 10 counties’ jails held nearly 58,000 inmates, about 7,600 more than their rated capacity.

Beyond the realignment law adding to jail crowding, county sheriffs say it also changed the nature of the inmates they are overseeing.

Only those convicted of violent, sexual or serious crimes now go to state prisons, leaving so-called lower-level criminals to serve what can be years’ long sentences in local jails that were designed to hold offenders for no more than a year. Parolees who violate conditions of their release also now generally serve their time in county jails.

In Sacramento County, assaults on jail employees soared 164 percent, the greatest percentage increase of any large county. Yet its jail population has not grown and remains near its rated capacity of 4,125 inmates.

The AP collected statistics from the 10 counties with the largest jail populations through requests under the California Public Records Act after officials said there is no statewide database tracking inmate-on-inmate assaults. Of the 10 counties surveyed, eight had increases in their jail populations between Jan. 1, 2011, and Jan. 1, 2013, while Alameda and Sacramento counties had declines.

Sacramento County was the only one to see a decrease in inmate-on-inmate assaults, while Alameda, Los Angeles and Santa Clara counties saw declines in assaults on staff.