At least 300 inmates were killed Wednesday in a fire that swept through their Honduras prison, the Associated Press reported.

About 356 prisoners are unaccounted for, out of 852, and most could be dead, according to local authorities.

The fire broke out Tuesday night in the town of Comayagua 90 miles outside the country's capital. Fire officials said the scene was "horrific" as about 100 prisoners were burned to death in their cells. The prisoners were difficult to evacuate because neither the cell door keys, nor the guards who had them, could be found.

Authorities said it would take at least three months to identify some victims due the severity of their burns and that DNA tests would be required.

The death toll is expected to rise as authorities investigate whether the fire was started by rioting inmates or an electrical short-circuit.