More than 1,000 more volunteer posse members are needed for patrols that the sheriff launched last month just outside schools to guard against shootings.
The new members are needed to augment and expand the program that will likely be reinstituted in the fall, Maricopa County Sheriff Joe Arpaio said.
People interested in volunteering are asked to call the sheriff's office at 602-876-1895 during work week business hours.
Arpaio oversees the nation's largest volunteer sheriff's posse, with 3,450 members. Critics say Arpaio launched the patrols to grab headlines.
The sheriff plans a training exercise Saturday aimed at helping his volunteer posse members respond to school shootings.
The exercise at a closed school site in Fountain Hills will simulate scenarios posse members might encounter during a school shooting.
Action-film star and posse member Steven Seagal will serve as an instructor at the event.
Officers will portray gunmen during the training, while 25 teenagers will play the part of students.
Four scenes will be offered simultaneously and each will be in separate parts of the school.
Non-lethal projectile guns will be used in the exercise.
Copyright 2013 Associated Press. All rights reserved. CBS 5 (KPHO Broadcasting Corporation) contributed to this report.