Up to 30 inmates at a Northern California jail threw punches at each other when a huge brawl broke out in front of security cameras installed only 24 hours earlier.

Santa Clara County Jail officials were about to hold a press conference announcing the installation of the cameras on the facility’s fourth-floor maximum-security cell-block when the fight broke out, according to Fox affiliate KTVU.

The San Jose jail was placed on lockdown for several hours as about 20 deputies used pepper spray to subdue the brawling inmates. No one was seriously injured, the station reported. The melee was reported just after 3 p.m. Thursday.

“It looks like one inmate brushed up against another and then the fight was on with fists,” Sheriff Laurie Smith told KTVU. “You can see a lot of fist fighting going on in the video. The inmates are spread throughout the pod.”

The jail installed 12 security cameras on Wednesday that Smith purchased with her own money at a Costco. She expects the $761 purchase to be reimbursed by the county, the station reported.

Smith went to Costco after being told it would cost $20 million and take two years to install security cameras throughout the jail and other lock-ups.

She called for more cameras in the jail after the beating death of an inmate last August. Three correctional deputies charged in the death are currently on trial, the station reported.

The sheriff said investigators will examine the video to see who started the fight, who was assaulted and who was involved.

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