Five inmates were killed and over 250 evacuated after a fire broke out during a riot in a prison in western Indonesia, police officials said on Saturday.Indonesia's national police chief Badrodin Haiti said some of the inmates at the Bengkulu prison on Sumatra Island started the riot on Friday night when officials tried to move one of the inmates, convicted of drug-trafficking.Haiti said the prisoners started the fire, which lasted two hours and forced 250 inmates to be evacuated, Efe news agency reported.Earlier this week, the Indonesian police and army launched an operation against drug- trafficking and consumption in the country, including that which occurs within prisons.