Danilo Orellana, head of the Honduran prison system, said survivors of the blaze reported that a fellow inmate set fire to his bedding and shouted, "We will all die in here," the Associated Press reported.
Orellana did not identify the man or his apparent motive.
Honduran authorities say they believe the death toll in the fire is now above 300, though they had confirmed only 272 deaths. The country's human-rights commissioner, Ramon Custodio, said on Honduran radio that 357 people remained unaccounted for.
The blaze broke out late Tuesday night at the federal prison in Comayagua, about 90 miles north of the capital, Tegucigalpa. Many trapped inmates burned to death or were asphyxiated in their cells. Authorities said rescuers were unable to find guards who had keys to the cells.
"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.
He said there had been 60 prisoners packed into his cell, according to AP.
Some inmates were able to escape by breaking through the roof, Honduran media reports said.
Photographs taken at the scene showed relatives of inmates gathered outside the fence of the prison, throwing stones at guards in anger and frustration and clashing with officers.
The facility was described as a farm in which inmates cultivated crops and raised pigs. It held an estimated 850 prisoners.
The fire has drawn attention to dangerous conditions in prisons in Honduras and elsewhere in the region. Across much of Latin America, prisons are severely overcrowded, filthy and poorly equipped.
In Honduras, more than 100 inmates died in a riot and fire at a prison in San Pedro Sula in 2004, and at least 69 were killed in a separate disturbance year earlier in La Ceiba.
Honduras has seen its murder rate soar to among the highest in the world amid growing drug trafficking and gang activity.
-- Ken Ellingwood
Photo: Soldiers run during clashes with the relatives of inmates after a deadly prison fire in Comayagua, Honduras, early Wednesday. Credit: Fernando Antonio / Associated Press