SANTIAGO, Chile – A fire started during an inmate brawl swept through an overcrowded prison Wednesday, killing at least 81 people and seriously injuring 14. Chileans heard the screams of inmates after a prisoner using a contraband cell phone called state television for help.

The early morning blaze at San Miguel prison, which preliminary reports indicated may have been intentionally set, was the worst disaster in the history of Chile’s penitentiary system, Health Minister Jaime Manalich said.

The fire began during fighting between inmates and reached its maximum intensity in just three minutes, Interior Minister Rodribo Hinzpeter said. It was brought under control in three hours.

Police operations director Jaime Concha insisted police acted quickly despite coping with 1,900 inmates at the prison built for 700.

“The conditions that existed inside this prison are absolutely inhumane,” said President Sebastian Pinera.

Chilean television broadcast spine-chilling audio and video from the prison fire, some of it shot by prisoners using cell phones and sent to stations.

The state channel aired a recording of an inmate calling from inside the prison and pleading for help. Screams could be heard in the background. Other broadcasts showed the smoked-filled prison tower and inmates shouting over and over: “The doors!” and “We’re burning!”

Private Mega TV broadcast a recording made by a prisoner of inmates in the burning tower screaming “Help! Help! Open the doors!”

Investigator Alejandro Pena said preliminary reports indicated the fire was set intentionally, but he didn’t say by whom. An inmate, however, told state television the fire began when a small stove fell during a fight.

Santiago region Gov. Fernando Echeverria said the official death toll was 81. Wednesday evening, officials had identified 31 of the victims. Officials said most would have to be identified by DNA.

Firefighters said they were alerted to the fire by a call from a cell phone inside the prison.

A fire department communique said the first firefighters arrived nine minutes after the initial alarm at 5:48 a.m., and found a violent fire spread over a large part of the fourth floor of Tower 5. They cut through several locks, allowing them to save 60 inmates, it said.

Hundreds of anxious and angry relatives of inmates gathered in a chaotic scene outside the prison gates. Some waited six hours before officials read out the names of survivors – which people mistook for those of the dead.

There had been warnings of problems at the prison.

In October, Judge Ana Maria Arratia Valdebenito said that Tower 5, where the fire began, held 484 prisoners — more than 100 per floor.

National Human Rights Institute director Lorena Fries said the overcrowding in Chile’s prisons is a problem that has been noted by the United Nations. The country has “55,722 people in its prisons, which have a capacity to hold 31,576 inmates,” she said.

Many of the inmates in the burned tower were first-time offenders. Among the dead was 22-year-old Bastean Arriagada, who was serving a 61-day sentence for selling pirated films.

Pedro Hernandez, who directs Chile’s prison guards union, said there were only five guards to watch over the prisoners. Chile’s president, however, said there were six guards in the prison towers where the inmates are held and 26 others stationed on the perimeter.

Some relatives of inmates told state TV that prison guards initially closed the gates to firefighters, impeding efforts by 10 units to control the blaze.

“They wouldn’t let the firefighters come in. The riot police came in first and began to beat us, and later the firefighters came in,” an unidentified prisoner said in a call that was played on state TV. He didn’t give his name, saying he feared retribution.