High-security prisons across California have tightly restricted movement, calls and visits while officials probe a surge in violence this year. The restrictions started Saturday and affect the top-security sections of nearly a dozen lockups including the California Correctional Institution,

Los Angeles County and other state prisons are upgrading their security after a recent surge in violence against staff and inmates. The California Department of Corrections and Rehabilitation (CDCR) announced that it’s placing Level IV high-security sections within its facilities on a modified program,

The day before state authorities announced plans to restrict inmate movement and revoke visits and other privileges, three inmates were killed in attacks at three different prisons.