TEGUCIGALPA, Honduras (AP) — Gang members in a women’s prison in Honduras slaughtered 46 other women inmates by spraying them with gunfire, hacking them with machetes and then locking survivors in their cells and dousing them with flammable liquid, an official said Wednesday.

The carnage in Tuesday’s riot was the worst atrocity at a women’s prison in recent memory, something President Xiomara Castro called “monstrous.”

Relatives said inmates at the facility had been threatened for weeks by members of the notorious Barrio 18 gang.

Chillingly, the gang members were able to arm themselves with prohibited weapons, brush past guards and attack; they even carried locks to shut their victims inside, apparently to burn them to death. The intensity of the fire left the walls of the cells blackened and beds reduced to twisted heaps of metal.

“A group of armed people went to the cellblock of a rival gang, locked the doors, opened fire on them,” said Juan López Rochez, the chief of operations for the country’s National Police.

Miguel Martínez, a security ministry spokesman, said the attack was taped by security cameras, up to the moment the gang members destroyed them in what he called a “planned” attack.

“You can see the moment in which the women overcome the guards, leaving them helpless, and take their keys,” Martínez said.

Castro said Tuesday’s riot at the prison in the town of Tamara, about 30 miles (50 kilometres) northwest of Honduras’ capital, was “planned by maras (street gangs) with the knowledge and acquiescence of security authorities.”

Castro fired Security Minister Ramón Sabillón, and replaced him with Gustavo Sánchez, who had been serving as head of the National Police.

But Castro but did not explain how inmates identified as members of the Barrio 18 gang were able to get guns and machetes into the prison, or move freely into an adjoining cell block. Initial reports suggested the doors to the gang’s cell block had been left open, facilitating the attack.

The amount of weaponry found in the prison after the riot was impressive: 18 pistols, an assault rifle, two machine pistols and two grenades — all of which were smuggled into the prison.

“Obviously, there must have been human failures,” López Rochez said. “We are investigating all the employees at the centre.”

Sandra Rodríguez Vargas, the assistant commissioner for Honduras’ prison system, said the attackers “removed” guards at the facility — none appeared to have been injured — around 8 am Tuesday.

Twenty-six of the victims were burned to death and the remainder shot or stabbed, said Yuri Mora, the spokesman for Honduras’ national police investigation agency. At least seven inmates were being treated at a Tegucigalpa hospital.

The riot’s death toll surpassed that of a fire at a female detention centre in Guatemala in 2017, when girls at a shelter for troubled youths set fire to mattresses to protest rapes and other mistreatment at the overcrowded institution. The smoke and fire killed 41 girls.