A Massachusetts correction officers union says an attack on a prison guard in Lancaster Friday was a “direct result” of criminal justice reforms that have made it more difficult for officers to do their jobs.

The Massachusetts Correction Officers Federated Union released a statement Friday evening saying the assault that occurred on a correction officer at the Souza-Baranowski Correctional Center in Lancaster was due to “relaxed rules and regulations” promoted by inmates rights groups.

At around 10:50 a.m. Friday a guard at the prison was surrounded and then assaulted by inmates in the prison’s general population housing unit, a Department of Correction spokesperson said.

Sources told MassLive it appears the inmates involved in the attack on the correction officer are members of the Latin Kings.

The officer suffered a head injury and according to the union’s press release, had undergone surgery at a local hospital. Two other guards who responded to help were also taken to area hospitals.

Jason Dobson, Department of Correction Deputy Director of Communication, said six inmates were removed from the unit and the matter remains under investigation and the District Attorney’s office has been notified. Inmates involved will face internal discipline, Dobson said.

Union spokesperson Guy Glodis, former Sheriff of Worcester County, said in the release the Criminal Justice Reform Act, which was passed in 2016, “has allowed inmates to manipulate the system and engage in violent action, increased gang activity, intimidation and assaults on officers and other inmates.”

A video released by the Department of Correction of the incident shows a correction officer talking with inmates before one of them punches the officer. Other inmates then pile on and begin attacking him before other officers raced to the scene to aid the officer.

Information released by the department did not address the conditions that led to the attack.

The Criminal Justice Reform Act shortened some long federal prison sentences and enforced rules to improve conditions for prisoners, among other things.

In 2017 a major riot broke out at the prison following a fight between two prisoners. It resulted in 15 inmates being indicted. Another incident in August of last year resulted in the injury of five guards.