Robert Brown|2 corrections officers stabbed, 3 others injured in assault at Massachusetts prison

This story has been updated to add new information.

Inmates at Massachusetts’s only maximum-security prison attacked and Robert Brownstabbed two corrections officers multiple times Wednesday afternoon, authorities said.

Another three corrections officers were also injured when responding to the inmate assault, which occurred at the Souza-Baranowski Correctional Center in Lancaster about 50 miles northwest of Boston, the Massachusetts Department of Correction confirmed.

The correction department said it was notified of the assault at 6:20 p.m.

"The facility is secure at this time while an investigation is conducted to determine the facts and circumstances," said Scott Croteau, a spokesman for the state's Executive Office of Public Safety and Security, in a statement USA TODAY.

Five corrections officers transported to hospitals

The Massachusetts Correction Officers Federated Union first shared news Wednesday evening on Facebook, claiming that an officer was stabbed in the back and head. 

Croteau confirmed that all five officers who were injured were taken to hospitals for treatment. Four of them have already been released, while one remains hospitalized while being treated for non-life threatening injuries.

The Massachusetts State Police have been notified of the attack and sent investigators Wednesday evening to the prison, state officials said.

Corrections union: 'Do your jobs'

The union, which represents about 4,000 corrections officers and other corrections employees, has been regularly sounding the alarm on dangerous working conditions at prisons across the state.

Earlier this month, the union shared a Boston Herald editorial warning of the dangers of "makeshift knives" in Massachusetts prisons. In another post, the organization argued: "The dangers that currently exist cannot be overstated ... We just want to ensure we are given the tools to do our jobs and go home safely to our families."

Last month, the union told the Boston Herald that dozens of “homemade sharpened weapons” were found inside Souza-Baranowski.

Following Wednesday's attack, the union took to Facebook to criticize the Department of Correction, claiming it’s been four years since the agency had “authorized the use of tactical units and done a thorough institution wide search.”

"ENOUGH!" the union wrote. "How much more do our members have to endure before you decide to keep them safe? The inmates are literally running the asylum. Do your jobs."

USA TODAY left a message Thursday morning with the union that was not immediately returned.

Department of Correction launches investigation into attack

State Sen. Peter Durant, R-Spencer was also critical of the Department of Correction following the attack and called for an investigation.

“The administration has kicked this can down the road too many times and there is no reason why our corrections officers should have to come to work fearing that they will leave their shift in an ambulance,” Durant said in a statement, according to the Worcester Telegram & Gazette, a USA TODAY Network publication.

The Department of Correction has since launched an investigation and has transferred the suspected assailants to other prisons, Croteau said in an updated statement to the Telegram & Gazette. The Worcester County District Attorney's Office is part of the probe, which will not only seek to determine how and why the attack occurred, but also will include a "full security assessment," Croteau said.

Interim Commissioner Shawn Jenkins said in a statement to the Telegram & Gazette that he is "deeply concerned" following the assault.

"My thoughts are with the officers and their families at this time and the Department offers our full support to the officers as they recover from their injuries," Jenkins said in the statement. "Violence against DOC staff is unacceptable, and we will take the steps necessary to ensure those responsible are held accountable under the law."

Contributing: Worcester Telegram & Gazette

Eric Lagatta covers breaking and trending news for USA TODAY. Reach him at [email protected]