Security Minister Pompeyo Bonilla said authorities had confirmed the deaths of 272 inmates “but we believe there are more than 300” fatalities at the Comayagua prison.
Separately, Human Rights Commissioner Ramon Custodio said that of the more than 850 inmates housed in the prison, 357 were unaccounted for.
“It does not mean that every one of them is dead,” the official said, noting that some might be injured or had escaped during the fire. Dozens of burned inmates were taken to hospitals in the central city of Comayagua.
The prison fire, the world’s deadliest of the past decade, was believed to have broken out around 10:50 pm Tuesday (0450 GMT Wednesday). Investigators were looking into whether it was caused by an inmate or by a short circuit. “We are pulling out bodies,” said prisons director Danilo Orellana.
“The situation is serious. Most have suffocated,” he said, adding that the fire did not appear to have been caused by a riot.
Witnesses said some of the inmates escaped the blaze by jumping from the prison rooftop, and there were reports that some of them had fled the facility and were on the loose.
The prison is located some 500 meters from a highway that links San Pedro Sula, the economic centre of Honduras, with Tegucigalpa, the seat of the federal government.
Meanwhile desperate relatives waited for word about the fate of their loved ones. At the break of dawn Wednesday there were already hundreds lined up at the prison gates.
“My brother Roberto Mejia was in unit six,” said an emotional Glenda Mejia.
“They’ve told me that the inmates from that unit are all dead,” she told AFP.
Next to her, Carlos Ramirez was waiting outside the facility for word about his brother Elwin, imprisoned on a murder conviction, who also was housed in unit six.
“I haven’t been told anything,” Carlos Ramirez said, his voice breaking.
It was the worst disaster to strike a penal facility in Honduras in years.
Latin American prisons are notoriously overcrowded, particularly in impoverished Central American states like Honduras, which are gripped by gang violence and drug trafficking.
The most recent similar disaster in Honduras, in May 2004, killed around 100 inmates during a fire at a prison in San Pedro Sula, which was blamed on structural problems at the facility.
Honduras’s 24 overcrowded penal facilities have room for 8,000 inmates, but the number is more than 13,000.