A prisoners' rights group is criticizing the state's correction officers union for its claim that criminal justice reform is to blame for a violent incident at a central Mass. maximum security prison last week that left three officers injured.

"This is a direct result from the recently enacted Criminal Justice Reform Act legislation, which was promulgated by Inmate rights groups and activists," the Massachusetts Correction Officers Federated Union (MCOFU) said in a statement.

Advocacy group Prisoners Legal Services (PLS) released a statement of its own in response, calling the union "wrong and irresponsible."

PLS Executive Director Liz Matos said the 2018 act did not influence Friday's incident at the Souza-Baranowski Correctional Center, located near the Lancaster-Shirley line. A Department of Correction video shows an attack by inmates that injured three officers.

"Although violence should always be condemned in any jail or prison, it's a very difficult environment to work in or to live in," Matos said. "The violence that is happening there is by no means a result of the Criminal Justice Reform Act."

Matos said state correction officials haven't even implemented many of the reforms required under the 2018 act, such as limiting solitary confinement. Matos says her clients incarcerated at Souza tell her that the prison is tense for both officers and inmates and there is still retaliation against those incarcerated over an August attack on a correction officer.

"This specific prison has a long history of violence and a toxic culture," Matos said.

The union agrees it's toxic — although not for the same reasons. Kevin Flanagan, a spokesman for the MCOFU, says attacks at Souza are increasing.

"The culture is the inmates," Flanagan said. "They're there because they're bad. We're not talking about jaywalkers. These are the commonwealth's worst people. "

Specifically, Flanagan says, those incarcerated should have to work for privileges like more phone calls or time off for good behavior. He says the criminal justice reform law should make exceptions for maximum security facilities like Souza-Baranowski.

"The union is all for criminal justice reform. These inmates are violent. If they want more phone calls or more visitation, earn it," Flanagan said. "They should learn how to respect the laws of the prison and the laws of the commonwealth."

Someone who knows something about the culture at Souza is Darrell Jones. He spent seven years incarcerated there until his release in 2017, when a judge ruled that Jones didn't get a fair trial. He says both prisoners and guards are confrontational.

"I lived it and that culture is an aggressive culture on each side," Jones said. "Why would a prisoner risk a longer sentence or more punishment unless he felt like he had to fight?"

Both the union and the prisoners group are now asking to meet with state lawmakers. Matos said she's concerned about a crackdown creating a less safe environment. Flanagan is worried that it will be less safe without a crackdown.

The Department of Correction says its still investigating Friday's incident and it's not releasing the names of those involved.

Gov. Baker visited the hospitalized officers over the weekend. One of the three remains hospitalized.