The fire in a prison in Honduras was accidental, officials have said.

Theories that the fire was started deliberately by an inmate or the result of rioting have been rejected, as the death toll reached 360 on Tuesday.

A cigarette is now thought to have been the cause of the deadly blaze, most likely setting fire to bedding as an inmate fell asleep without first extinguishing it.

Cigarettes are one of the most common causes of fire and have been the focus of a recent national radio advertising campaign in the UK.

The European Union last year brought in rules for all cigarettes sold in EU states to be reduced ignition propensity cigarettes, meaning they extinguish quicker when not actively smoked.

Chief prosecutor Luis Alberto Rubi told local television that none of the 277 autopsies so far carried out has revealed any evidence of gun shots.

He explained that witnesses had suggested the theory that an inmate fell asleep smoking, and that this was supported by officials from the US Bureau of Alcohol, Tobacco, Firearms and Explosives, who have been brought in to assist in the investigation.

With the investigation into the cause of the fire reaching initial conclusions, the focus is now likely to move on to why firefighters were unable to save more of the 800 prisoners held at the jail.

Comayagua prison was designed to hold 500 people, so overcrowding was a big factor in the high death toll.

But criticism of the actions of guards on duty is also likely to be forthcoming in President Lobi’s “full and transparent” investigation.

Firefighters had difficulty getting into the building as none of the guards with keys could be found.

The investigation continues.