Gang violence in New York City jails surged to a 15-year high in July with a bloody attack occurring on average about once every 34 hours inside the city’s detention centers. At least 16 of the 22 shank attacks reported last month at Rikers Island, the city’s main penitentiary complex, involved intergang rivalries.

“It’s pure savagery,” Ed Gavin, a retired deputy warden, told the New York Daily News, which obtained the prison-violence data. The paper described one attack involving eight gang members who slashed a fellow inmate during religious services in a jail gymnasium July 1.

The increase in gang violence in one of the largest jail systems in the country is stark. In July 2014, seven slashing or stabbing incidents using improvised sharpened objects were reported, which means last month’s data mark a more than threefold increase in attacks compared to the same month last year. So far this year, 711 inmates have been caught committing violence against other inmates at Rikers.

New York City Mayor Bill de Blasio and Correction Commissioner Joe Ponte recently announced a 14-point plan to tackle the rising problem of violence in the city’s jails. Measures include more searches for drugs and contraband and new housing arrangements to segregate gang rivals.

“We will aggressively tackle inmate-on-inmate violence by stopping the flow of weapons and drugs into our jails and stanching the flow of information that enables gang members to commit violent acts across facilities,” Ponte said.

New York state gang prevention specialist Ron "Cook" Barrett said part of the increase in intergang rivalries in the city has to do with an influx of Latino gangs into the state.

“Every nationality is represented within the gang culture,” Barrett told Vice in a report published Aug. 18 about New York City’s evolving gang culture. “With the African-American population in New York state prisons being the largest, the gangs will reflect that. In California, for example, because of the Mexican population, the Mexican Mafia -- Sureños, Nuestra Familia -- are the power groups. With the Hispanic population growing in New York state, these groups are starting to become more visible in our state.”