A prison riot broke out in the Australian city of Melbourne Tuesday, the day before a total smoking ban in jails is scheduled to take effect. Prison staff were evacuated as a precaution, police said. A helicopter from a commercial TV station filmed stick-wielding prisoners in the yard wearing masks and bashing down doors. A half-dozen fire trucks were parked outside the prison, which is on the outskirts of Melbourne. Around 300 prisoners were involved in the riot with some reportedly lighting fires inside the grounds, reports said.