Many of the inmates killed in Comayagua prison, 45 miles outside the capital of Tegucigalpa, were trapped in their cells, according to the Interior Security Ministry. By Wednesday afternoon, the confirmed body count had reached 272.
Photographs in Honduran dailies showed prison dormitories with twisted metal beds and rows of charred bodies lumped in the hallway.
Prisoners were heard screaming in their cells, and most suffocated, Director of Prisons Danilo Orellana told the Honduras Herald. After an initial investigation, prison officials concluded that the fire was not sparked by a riot, Orellana said.
"We have two hypotheses, one is that a prisoner set fire to a mattress, and the other one is that there was a short circuit in the electrical system," Orellana said.
Honduran President Porfirio Lobo convened his cabinet and intended to address a nation already battered by corruption and one of the world's highest murder rates -- four times that of Mexico. In order to avert public unrest, he has suspended the head of the prison and the director of prisons.
Jacquline Cassanova, of the Honduras Defense Ministry, told ABC News that military units had moved into Comayagua to track down some of the inmates who may have escaped, and to restore order.
Hundreds of family members crowded the area as the names of more than 450 survivors were read out loud.
"This is desperate, they won't tell us anything, and I think my husband is dead," a crying Gregoria Zelaya told Canal 5 TV as she stood by a chain link fence.
Local firefighters said gunfire prevented them from entering the prison.
Among the dead, reported the Herald, were the spouses of inmates on conjugal visits. A prisoner identified as Silverio Aguilar told HRN Radio that someone started screaming, "Fire! fire!" and the prisoners called for help.
"For a while, nobody listened. But after a few minutes, which seemed like an eternity, a guard appeared with keys and let us out," he said.
In 2010, President Porfirio Lobo declared a state of emergency at nine of the country's 24 prisons.
Lucy Marder, chief of forensic medicine in the prosecutor's office, told the Associated Press that 12 victims had been treated and nine more were at the Hospital Escuela in Tegucigalpa, bringing the total injured to 21. "We think the death toll will rise," she said.
Marder said it would take at least three months to identify victims. Because some were burned beyond recognition, DNA tests would be required.
Across Honduras, prisons are reportedly filled to double their capacity, with about 12,500 inmates in prisons meant to hold 6,000. More than 100 prisoners were killed in a fire in the textile manufacturing town of San Pedro Sula several years ago, and survivors said later that guards fired on prisoners trying to escape the blaze.
Comayagua had 850 prisoners on its books, which far exceeds its intended capacity.
The highest official death toll in a prison fire previously was 322 at the Ohio Penitentiary in Columbus, Ohio, in 1930.