RIVAS, Nicaragua (AA) — At least 16 people were killed during a riot at a Guatemalan prison, officials confirmed Monday.

“The current situation is the confirmation of 16 dead, one by firearm and the others by bladed weapons”, said Vice Minister of the Interior Elmer Sosa.

Authorities who are still processing the crime scene and the remains of the dead believe the Sunday massacre was likely the result of an armed conflict between gang members and other inmates.

“Investigations continue, but it is confirmed that no inmate managed to get out past the guard posts”, said penitentiary system spokesperson Rudy Esquivel.

Police special forces continued operations Monday to regain control of the Canada maximum security prison after additional police arrived from other regions of the country. Soldiers are also on scene.

“Immediate action was not taken to avoid confrontation between inmates and police”, said Sosa.

Officials met Monday to analyze the incident and examine urgent measures to prevent similar incidents in the prison system, according to the interior ministry. Defense, police, penitentiary, and human rights officials also participated in the meeting.

New measures will include the rotation of penitentiary guards among the country’s prisons. One guard was detained Monday for attempting to tamper with evidence.

Prison visit and search protocols will also change, said officials. A gun, knives, cell phones and marihuana were found Monday during a search of the prison.

Popularly known as Hell or The Little Hell, the prison is located in Escuintla, 40 miles southwest of GuatemalaCity. It is home to 3,092 inmates – more than five times its capacity of 600.

In April, penitentiary officials found a nearly completed escape tunnel inside the same maximum security prison. Five inmates escaped the following month.

The prison director was gunned down in 2012 in Escuintla. Guatemalan president at the time Otto Perez Molina stated that gangs operating inside the prison likely orchestrated the murder.

In 2001, 78 inmates escaped. Many of the captured escapees went on to organize another escape in 2005.